Despite some minor flaws and a somewhat short single-player campaign, it's hard not to recommend Call Of Juarez: Bound in Blood to anyone who enjoys first-person shooters. It's a breath of fresh air in the midst of the usual bald-marine-in-a-power-suit type of shooters. It oozes atmosphere in each and every level, has some incredibly satisfying gunplay, and also features some of the best voice acting this side of GTA.
Until Red Dead Redemption comes out (and hopefully blows people away) this will remain as the definitive Western-themed game. So if ya lookin' for a game that ain't generic, has a good story, well-developed characters 'n some awesome action, give it a try. Won't regret it son, tell ya what.