These days I have been playing Flatout 2. Quite nice! I especially enjoy the multiplayer Derby mode. A lot of fun - especially if you were fan of Destruction Derby or Viper Racing. I am impressed by how well the network engine copes with all the simultaneous collisions. I guess there is a lot that is asynchronous (barrels, and flying car pieces are probably not in sync) but the car-against-car collisions are nicely consistent.
I always wanted to make a fighting car game. There has been some in the past (the famous Interstate, and more recently Auto Assault - there is a list of those games on Wikipedia :-) ) but I would like to do something much more action oriented. A derby between cars with machine guns on turrets, missiles, flame thrower, chainsaw on the side, and other cool nasty weapons. Ah well, maybe one day ;-)