Speaking about Oracle (+) syntax and LEFT/RIGHT [OUTER] JOIN syntax there is a difference. And it is nicely described here
http://www.oreillynet.com/pub/a/network/2002/10/01/whatsinacondition.html
Speaking about ANSI syntax where everyone has to explicitly say to make CROSS JOIN to get Cartesian product at least in Oracle it is not true, using stupid (at least to my mind) NATURAL JOIN clause one can easily get CROSS JOIN and also JOIN on such columns he never thought it really is. I’ve blogged about it here
http://gplivna.blogspot.com/2007/10/natural-joins-are-evil-motto-if-you.html
Don’t know wehether it is just Oracle specific or as per ANSI SQL standard.
Speaking about INNNER JOINS as a Cartesian product and then eliminating all unnecessary rows, at least the real mechanics in Oracle is absolutely different, there are following possibilities for doing them:
NESTED LOOPS (OUTER)
HASH JOIN (OUTER)
MERGE JOIN (OUTER)
and for Cartesian product it uses MERGE JOIN CARTESIAN, and that’s when usually the real trouble (filling temp) starts 
The real choice among Nested loops, hash join or merge join at least depends on data, statistics, available memory for a session, explicitly given available memory for hash joins or merge joins (btw there is possibility to give for one but not for other), system workload, hints, initialization parameters allowing ceratain join types (at least for hash joins) and probably something other 