Currently I am trying Crysis and Oblivion. Crysis is going to kill your PC, u will need atlest 880GT 512mb and 2 GB ram and 2.67 GHz Core 2 Duo, to play it on very high in XP.
Then u will never want to look at anyother game except Half Life 2 for Graphics. Yup HL2 is that good and that too when it came out in 2004. Just it doesnot have the forests of Crysis Quality. But its performance on lower hardware is amazing, thats why it is also so great. Why did Crysis dont have some Static Pre Computed Radiosty Lighting system nad compatibility modes so that it could run on atleast nvidia 6200. Eeks. Seriously than lots of people could have experienced this great game. Unreal Tournament 3 has only Warfare gametype which is good, on rest all counts UT2004 is amzing. Though I play bot. Waht is with sequels. Battlefront 1 is amzing but Battlefront 2 is so bad. Atleast Crrysis is lot better than Far Cry. Actually after looking graphics for first 2 days I amreally impresed by its gamepaly. And Oblivion is already undisputedly great game.
I remember at GDC IBM tried to run Crysis on their laptop and it sinked the laptop in Oblivion. Except Crytek(on their alien hardware), no other comapany could run Crysis at very high settings in 1920 resolution (whatever hardware they tried). Though nvidia came close. It seems only 5 entities can play this game – Crytek, EA, Bill Gates, Nvidia, George Bush.
The reason basically is that Crytek made Crysis so that it stresses out any known hardware(like Far Cry). And they specifically wanted to make the prettiest game ever. But I think a game should be made compatible with cheap lower hardware too. It is bit of not so good that nvidia 8800GT blasts any known game, still it is just sufficient enough to play Crysis at low resolution without antialiasing and then it gives barely 30 FPS that is required. Not to mention that nvidia is the best card manufacturer(cheap and good) and Value for money for 800GT is amazing and unmatched. U dont need a card other than that for maybe 2 years and it is very cheap.