I think twin SLI is the only way to go with Crysis, although it sounds like even a twin 8800GT set up still isn't enough to play very high detail at even 1920x1080 res. at a good frame rate. If that's so, even a twin 8800GTS 512MB card set up wouldn't be much better.
I'm going to pick up a copy tomorrow. As luck would have it, it's $20 currently at Circuit City on sale, which is pretty much the same as giving it away.
http://www.circuitcity.com/ccd/howToGetIt.do?c=1&zip=95070&oid=196943&originURLEncoded=







