Co-op help

Me and some friends are planning a bit of a LAN party (about 5-6 of us)
I'm just wondering wot games people here recommend. for co-ops
so far we're thinking about Diablo 2, Battlefield 2 (+Vietnam), titan Quest,
FEAR (mod).... After that we get stuck, any advice? :)

Thanks in advance.
Ollie

PS. Not really into Star craft type games

Yes,

Vietcong 1&2 , Farcry , Battlefield1942 MOD Desert Combat , Counter-Strike Source and 1.6 , Call of duty 1&2 

Also, say i can get one/all of these games can i install it on each machine in LAN (same disk)
and then play them if we get a no-cd patch thingy, if we dont connect to the net will
the game know and let us play? Or will i have to purchase lots of versions of the game ?

Sorry for newb question, i know nothing about comps :D