I would suggest u to wait for PS3. If u don't wanna wait than go for PS2 instead for a gfx card coz if u buy PS2 u will be able to play each and every available on PS2 for years but if u buy a gfx card u won't be able to play games coming in 6-7 monhts properly coz they would be heavy on ur system.
I recently got a new rig with asus 3200+ , a8n-e , xfx geforce 6600gt(256) abd 1 gb ram and i m not able to play F.E.A.R on 1024*768 and that games elders scrollblivion won't run even on medium settings on my pc so I would suggest to gor for PS2. It is better to wait for PS3
Well .. consoles are not upgradeable ... but lasts for more than 3-4 years at a stretch .. if u want a solution that'll have a one time investment go for a console .. but if ur a hardware fanatic ... pc is the way to go ..