I stand corrected!
However! Recently I have just acquired a beast of a computer, running all settings on high. (I know there's very high, but I'm guessing that's for 64bit memory) The game, is completely different. The amount of mediocre KPA activity on previous plays through has been changed to moving more often then you originally remember. Even the interactions with the environment are vastly improved, (ie, running down a KPA doesn't just make them go through the car or stop the car completely) Not to mention the graphics are mind numbingly impressive (which was kind of a given). The difficulty however, is a little bit more difficult, but still pretty easy for Delta.
If your thinking just upgrading your graphics card will suffice for this game. You are not very good with computers, and you should feel disappointed when you try and play and it still sucks. Upgrading your RAM to a more then a standard 553mhz, is a good move. Upgrading, your CPU to a Core Duo or Quad (quad, no really point unless you actually do stuff with your computer other then gaming) that is above 2.5ghz. Getting a new mother board to handle it all. And lastly, upgrading your Graphics card, 8800s should have no worrys at all running it, but as long as the other parts in your computer are upped as well, and 8800 isn't completely necessary (especially when your budgeting). Don't just buy stuff cause you think they're good, check out there specs, and see the differences.
Summary, Crysis is way better on a awesome computer, and way worse on a crap computer. And if you think this game sucks, well... it's your own fault for running it on a crap computer.