So far, Rainbow Six Rogue Spear/Urban Ops has my vote with Lloyd's Weapons Mod 7.0x
I think there are over 300 rifle choices and 100 pistol choices.
There are a number of AR-15 variants, like the M4 SOPMOD with ACOG and Suppressor, M16A1 with M193 ammo, Mk 23 SOCOM .45 ACP pistol, Knights SR-25M w/ suppressor (basically Navy Mk 11 Mod 0 rifle system - 7.62x51mm looks like the SPR), Tromix .50 AE/.458 SOCOM/.44 Magnum, and etc...
The only prob is that the game engine sucks. I wish there were large weapons choices like this available with the Unreal 2 engine like the one from AAO.
I can't wait til they put a Liberator into a game!
It always seems like when they get one thing right in a game, something else is always out of whack.