Commandos is legendary.
A more recent title I was thinking of the other day, was Unreal Championship 2 for the original Xbox. It came out late in the system's lifespan and was a sequel to Unreal Championship which was a completely forgettable, stripped down UT clone. However, the sequel went for the innovative and tried to do a lot of different things that weren't necessarily "Unreal." I mean, you played it with a
controller-- it was a different beast.
The lore was surprisingly fresh and the melee combat was sooooooooooo satisfying. You could mix up combat rules like physics and gravity so that you had everyone flying around the arena like gods. Unfortunately, Xbox live hadn't really developed at this point and you could only split the screen for two players locally (instead of four). Still, it was a great change of pace at Halo LAN parties. I recall the "freeze-fatality" combos fondly.