Unreal Tournament 2004

The thing about Onslaught is that while it's great fun, it's always the same. It just happens on different terrain. The same strategies always work, and everyone whores the same vehicles. Assault is great because every map is truely unique. In this one, you have to recover these missiles on a moving convoy while on foot. In another, you're trying to steal a tank prototype (I think), and you get to actually drive and use the tank in the process; then there's the mothership one with the space combat.