Hey, guys, original poster here. First, let me say that you guys ROCK !! I love Anandtechie's. AT'ers? Thanks for making me feel so welcome on my first post.
Anyway, some details to fill in that will help paint the picture:
-- love all the advice
-- I am glad that everyone agrees the GPU before the CPU
-- and, yes, the RAM needs to get better than 512MB, just depends on $$
LCD: 1280x1024 max res
RAM: NOT the Rev.2 -- just plain old Platinum
OS: WinXP Pro SP2
Arctic Silver 5 between CPU and stock HSF
Goal: upgrade current system to better, and hopefully longer term, have possibility of running MS Vista in the distant future as a 2nd PC. MAYBE a year or so from now, build a whole new 2nd PC on socket AM2 and Vista.
Now back to GPU: I like that NVidia is relatively "easy" to figure out right now:
$120 = 6600GT
$200 = 6800GS
$300 = 7800GT
$400 = 7800GTX
and just choose your price point since performance approximately scales with price for NVidia cards. But I haven't followed ATI as closely. If someone could provide a rough list like the one I just wrote, that would be cool.
As for a 7800GT, I have 2 questions: 1) I've heard that 7800's have some subtle display quality issues, and 2) would there be any difference between the $270 eVGA that ends in -N515-AX vs. -N516 at $300? I couldn't tell.