2 Player LAN game recommendations

As per the title, looking for all good 2 player LAN game recommendations.

PC's are pretty modern spec so anything goes. Got the gigabit LAN set up and just need a few games.

Current favourites are:

Hidden & Dangerous (Such an awesome game)
ARMA (Though struggling to find decent 2 player maps)
AIX 2.0 (Battlefield 2 mod)
Carmegeddon
Age of Empires II


Can anyone suggest some good ones? We'll take COOP or competitive. Any suggestions more than welcome.

Tom Clancy, blacklist was a great coop game, and portal 2 for sure.

Battlezone/2

Cool Lan game, dig deep on the mods if you go with it.

Total Annihilation

Dungeon Defenders

Orcs Must Die 2

The original Unreal Tournament

Quake 3 Arena

Serious Sam series

Borderlands 2