Fast boot drive and slower storage drive... absolutely.
I've haven't lost data in over 10 years now using this method.
Every time I vary from this I regret it.
If the boot drive gets corrupted it's very hard to resurrect it (heads often crash destroying data)... but I've never managed to kill the storage drive in 20 years.
Even my mates raid array crashed badly. It is a 5 disk raid array with 7 Terabytes. It's been ages and he still hasn't managed to resurrect it. He's a very good system admin and he's been working with the company that supplied the Raid hardware to try and bring it back up... still waiting for an update on this. BTW: This is not meant to happen to raid arrays!
This blog was written before SSD's became available. SSD's can do hundreds of I/O's at the same time... and access is virtually instant... so as a result they are a very good choice for speed (plus they are quiet and don't use much power). There's a bit of a question mark over reliability and price... but both are bound to improve. I'm keen to try one.
The reason most people have no idea about the bottlenecks in their systems is that they very rarely test them. This occurs even with the technically proficient and stretches across almost any other item as well. Only about 1% of the population test.
The only thing I disagree with a bit is the graphics... but that's because my usage is not graphics related... onboard graphics allows me to upgrade the motherboard about twice a year because it's so cheap. The newest integrated graphics chips have also improved onboard graphics immensely (Vista's rating system is helping) my Vista graphics rating is 3.5 (everything else is 5.9) NB. Don't use Vista if you want performance... XP is a better choice.
Other than that I think the graphics recommendation is spot on too. You don't need the fastest card to get pretty good system performance.
If you've got Vista then about 4GB or better (with 64 bit OS) is smart... as Vista seems to use all the available memory for caching when doing things like burning DVD's. Video editing is also likely to suck up as much memory as you can throw at it.
I still haven't decided if faster 1066 DDR2 is going to help... but on paper at least it's got twice the bandwidth of DDR2 800 memory... and that's a HUGE difference. Chances are you'll only notice the difference when you're doing something that the CPU can hold in memory then processes really quickly. It would have to be something fairly big and bulky to give you a meaningful performance improvement.
One thing manufacturers could do to help improve system reliability is to park the heads off the disks when the disk powers down or in between writes/reads. A capacitor to give the drive enough power not to crash in a power outage and give it a few seconds to allow it to park the heads would also be a good idea.
Some drives do park heads off the platters... but I don't know of any that have added a battery/capacitor to give them a few extra seconds of power so they can power down safely. SSD's basically solve this problem... but they're not yet widely available, big enough or affordable enough.