If you don't care about graphics, you won't find much game here.
There's a lot of interest in the game for its open means of completing objectives, but the storyline seems to fall on the underwhelming side, feeling rather poorly written. While sometimes I can let this slide, this is a game that is trying to sell itself on its atmosphere, and that makes the story all the more noticeable, because the gameplay, though innovative, just doesn't always feel entertaining.
It's sometimes hard to qualify that generic 'fun' factor in a game, but Crysis just isn't the sort of game that compels you to play through it a second time. Considering that, its really not worth it to upgrade your system just to play this game, the average person will find themselves with much better FPS options like Team Fortress 2 or Call of Duty 4 to sate their pallette. By the time PC technology catches up to Crysis's specs, better games will be out that take advantage of it, and Crysis, while remembered as a landmark, will be mostly forgotten by the gaming community at large.