I'm keeping this strictly 360 since it's in the 360 forum.
Brothers in Arms: Hell's Highway - It was at this point that the series went from beloved to pooh-poohed, mostly because it stuck to what it did best and didn't try to overstep. If you ask me, not every sequel needs to completely overhaul what was already established by its predecessor(s).
Kane and Lynch - Ultimately, this game speaks more of potential than actualization, but what remains is still worthwhile. There's a good, gritty urban tale that keeps you involved even if it is a bit derivative (of Heat especially). Co-op is the best way to play.
Army of Two - If you're going to play this one solo, forget it. With two players, however, the game changes miraculously into a solid afternoon of fun.