I agree with the posts that your use an external DAC instead of a sound card. I went with Nuforce Icon-2. It takes a USB input from your PC, and has special cables (CAT-6E RJ45 to RCA banana) for standard non-powered speakers.
I currently have it powering a pair of Paradigm Mini-Monitors that are resting on speaker stands next on either side of my desk. The combination sounds fantastic! My only wish is that Nuforce would come out with a newer version that had more than 24 watt per channel.
When you mention:
Thus, once you have a set of nice headphones, you do need some kind of amplified output for them.
Why do you need an amplifier for your good headphones? Are you using an amplifier for equalization purposes?
I have a Philips SBC HP800 for 5+ years now, and I find absolutely no need to keep volume at a high setting — and that’s on my laptop output, which is a Whatever Sound Card (Intel HDA). I do miss my SoundBlaster MP3+, but right now that’s what I have.
Most of the time I have the volume at 50%–60%. Up to about 80% when listening to Dream Theater or when the surroundings are noisy. On favorite songs, I will push to 90% or 95% for the duration. 100% is reserved for those favorite solos, for a couple minutes at most. On certain songs, I would barely hear the fire alarm if it sounded and the volume was 90% or more. And no, these headphones don’t have noise canceling.
With these headphones, OggVorbis (http://xiph.org/vorbis/) or FLAC (http://flac.sourceforge.net/) becomes a priority. Investing on top-notch headphones to listen to MP3 is kind of throwing money away.
Personally I use budget studio gear. Much better than anything you get at retail and largely cheaper too because they’re not pretending to be ‘luxury products for the discerning gamer/film enthusiast’. The build quality is generally superior.
@Cody Rather than tying yourself into a particular sound card for legacy functionality you like, you can use alternatives. The point here is that EAX-like functionality doesn’t require hardware, you can have applications do it in real time.
@Vilx Games use engine-bespoke software DSP nowadays. As a single example, all Source games use the same DSP http://developer.valvesoftware.com/wiki/DSP (and note, this is an old as hell engine). Again, no need for EAX. It’s already in the game.
Check out Focusrite VRM Box (http://www.focusrite.com/products/audio_interfaces/vrm_box/) for an interesting take on headphone usage - not just an excellent headphone amp, but also some nice speaker and room modelling which can reduce listening fatigue.
(full disclosure - yes, I work for Focusrite 
@Rushyo - Indeed. Profoundly disappointing. Imagine where the sound effects could be today if the audio silicone had evolved like the video silicone did! Instead of a generic “thud” when a dead alien hits the ground, you would hear a multitude of "splotch"es as the limbs hit the ground and each other, all precisely calculated and reflecting in the room and around the corners as they do in the real life. You could literally hear your teammates breathe down your neck as you step softly down a dimly lit tunnel towards the muffled cries of hostages. Your cloak would rustle in the wind and you could hear the chittering of squirrels as it echoes down the hollow trunk of the tree. The virtual haircut
would be a 5 years old demo on a dusty CD that came along your low-end sound-accelerator.
A good pair of headphones can rival expensive speakers. I like Goodcans, a web site completely devoted to headphones: http://www.goodcans.com/. Getting decent sound out of a laptop is abit more difficult, love some advice.
I am not a musician, nor an audiophile. I do, however, record vinyl from time to time, and I bought a little keyboard synth to play around with. Even audio-troglodyte moi noticed appalling quality of line in on an Intel “HD” onboard sound card.
I dug a 13 year old SB Live! out of storage and tried that – infinitely better.
Speaking of noise, it’s a shame to see the signal-to-noise ratio of facts in these comments tending towards the nonsense 
Too bad the Xonar DG does not work in Linux.
well - I am using external USB card Roland UA-25 and it has extremely gorgeous audio - there is NO AWESOME internal audio card on the market, it cannot be :)))
BTW works in Linux
I bought myself a Logitech G330; it comes with an external ADC/DAC. I doubt it’s as high quality as the ones that you mentioned - but is miles ahead of on-board solutions (although you might find because the two are designed for each other the quality could be high).
It also has built-in weak noise cancellation (if you use the ADC/DAC and plug in the microphone) - which really helps with concentration. If you have music playing at a ‘normal’ level it completely cancels out environmental noise.
The only thing is that the headphones are pretty heavy; it took me a month to get used to the weight on my ears.
@Adrian Petrescu and others, I agree the durability issue is a problem. I eventually went with the sennheiser 25-1-ii
http://www.head-fi.org/products/sennheiser-hd-25-1-ii-professional-headphone/reviews
These headphones are breathtaking. They are closed back and supra-aural so you can’t hear the person in the cube next to you. This also means you can reduce the volume to play it at to enjoy it, saving your hearing. ALL parts are user replaceable, so I’ve heard of pairs lasting 10-20 years (as long as the model as been out). I am fan of going with commercial grade quality if possible since they normally last longer than consumer grade material (at a higher cost of course). These are used in studios and TV’s. They are well worth the investment if you are daily listening to music.
Sounds like some of you have been unlucky with headphones. My Sennheiser HD280s are 7 years old and still going strong.
And the fidelity is as good as it can be (because it is better than my hearing, so there’s no point in me spending more on higher-quality phones as I would be unable to tell the difference.)
And if I remember right they cost UK£80 (with the exchange rates at the time that would have been equivalent to US$145.) If I bought a pair of speakers for $145 there’s no way they would sound that good.
I’m looking for an awesome external 5.1 solution. Most of the USB boxes I’ve tried have been unreliable. Any ideas?
As someone who actually does a lot of DSP work I have to disagree. Hardware channel mixing, audio latency, resampling, and so on are all often handled very poorly by multi-purpose processors. 3D and HRTF’s although ‘cool sounding’ are not the most resource intensive functions a card, or audio application will perform. ‘Perfect’ polyphase or bandlimited interpolation techniques will consume far more resources than they will. Most any processor today, including current i7’s, xeons, etc can be bogged down by resampling alone. Let alone noise shaping, dithering, hard limited, and so on. We’re a long way off from no longer needing sound cards. The only reason they wouldn’t matter is if audio quality isn’t something that matters. Which is sometimes the case.
Also onboard sound cards are generally atrocious. I’d put them about on par with your average onboard graphics adapter in quality. No sample rate switching, no hardware mixing, no hardware dac, high latency.
I realize this may seem pedantic, but really it’s not. The onboards aren’t crappy compared to some studio level expectation. They’re crappy by most standards. In many cases when you’re listening to lossy audio, sent through a crappy resampler, with a ton of gain added through some relatively low end speakers of course you’re not going to notice. When you start talking about high end headphones, or monitors however, it often will be noticeable in more ways than one. Your audio setup is only as strong as its weakest link, and if you’re using an onboard… it’s not your monitors/headphones.
i just got a Zacate as an HTPC. annoyingly there was a hum on the analog outs, both on onboard as well as a low-to-mid-range “audiophile soundcard,” a Razer Barracuda AC-1. probably my fault for running a 12 foot 1/8" to RCA.
i fixed it with a $30 USB DAC/Soundcard from Diamond (i really wanted multichannel, but $100 from Creative was a bit expensive “just to see if it would work”), and even tho it’s just 48/16, i’m impressed enough to speak up about it. it seems louder (higher line voltage, maybe?) than my old but broken workhorse, the Chaintech AV-710 as well as some crap X-fi.
I had that onboard sound chip before upgrading to a Xonar DG. Although I had no problems with onboard, I can clearly tell a difference.
But it should.I’ve used the Xonar DX in Linux for over a year! It’s the same DSP - as far as the drivers are concerned - on both the DX and the DG. In the DX case it’s the CMI8788 and on the DG it’s the CMI8786, which is the exact same DSP with some features hardlocked.
The drivers will identify it as a CMI8788. And support for CMI8788 has been present in the Linux-kernel and in ALSA for quite some time.
Linux even adds an Audiphile killer feature over the Windows-drives in the form of the possibility to trim the roll off of the DACs digital filter. Not sure if it’s supported on the lower specced CS4361 on DG but it works alright on the CS4398 of the DX. Switching the digital filter to the “slow roll off”-mode gives every sound a slight extra lifelike quality 
Also, it’s probable that it won’t be possible to trim the headphone output impedance on the DG, at least not yet. But it should definitely work as a normal soundcard.
I’d just like to point out that RightMark AudioAnalyzer measurements are worthless, it’s explained somewhere in here:
http://nwavguy.blogspot.com/
Even without checking the facts I’d assume that there’s a real difference between builtin Realtek and any proper discrete soundcard.
I’m using the not-so-well-known Teufel Aureol Real headphones, but according to people who’ve worn 300 euro cans and these 100 euro cans, the Aureol Reals certainly compete. Some even like them more. Teufel is a company from Berlin, so they only sell in Europe.
I’m investing in the X-Fi HD for a sound card, i’m a gamer and I heard that this card has some incredible virtual surround going on.
I think 200 euros total is a perfectly fine price for a pair of very well balanced and great looking headphones, a sound card and a microphone 