I've heard great things about America's Army and it's Sequel, but unitl I try them, the most *realistic* fps----without question----is:

Far Cry!

The Immersion level is the best of any game I've ever experienced or heard of (save the above).

The AI, comparing against the likes of HL, Ureal, and every other FPS I've played, is the most realistic.

Three caveates:

1) About a third of the way thru the game progressess from an excellent *jungle combat* game, to one a *monster* combat game. A bit Sczheprenic (sp?).

2) If sneaking around ala Thief, wasn't your cup of tea, the game might not be for you. The *Stealth* factor is huge.

3) To play the game at or near its maxium effect (the only way to play btw), you need a better than good system. ATI 9700 pro video card or better, at or very near a 3 gigahertz CPU, and a VERY cool system. Not to mention having the latest DX9, BIOS, Chipset Driver, as well as the latest drivers for ALL your hardware.

Far Cry is the most advanced game to date, more advanced than D3 and more than HL2 (at least compared to when HL2 was first supposed to be released).

Oh yeah, I forgot, MP leaves a bit to be desired. I wouldn't reccommend buying for *only* MP. Some people like MP, some don't. Yet, it has HUGE potential.