I basically rebuilt my system when I got Half-Life 2 and Doom 3 (at the same time), and I haven't had to mess with it since then; BioShock sails along nicely at 1280x1024, so I'm happy. The first three you mention were just before my time and I only played them after the fact, unfortunately. I understand Quake forced quite a number of hardware upgrades when it came out, though.

I think I did upgrade to a Voodoo2 in part because of Quake.

quake3 made me realise my v2 wasnt up to the job any more
got a gf256

ut2004 made me realise my gf2mx wasnt up to the job any more got a gf44200ti

oblivion made me realise my 7600gt wasnt up to the job any more got a 8800gts

That's interesting; Oblivion actually confirmed that my 7600GT *was* up to the job. I never had a single problem with it.

oh oblivion runs without problems but its slow if you max the detail

Games never made me upgrade. Dead parts made me upgrade.

Well Oblivion tought me not to buy crappy video cards like 5600 XT 😜
I got the 7600 gs and a 2.8 ghz processor and now I can run it at High lvl 😜

Oh, I can max the detail and still run Oblivion just fine, at least at 1280x1024 (which is all my monitor supports). However, I played the Crysis demo a few days ago; very pretty slide show. Might be time to start looking for upgrades again.