Me and my brother need one or two new MP games and I thought why the heck not try GOG? So hit me with your best alternatives! Maybe I even own a few good choices but haven't checked them out?

Ps: Co-op is a huge bonus and we're open to most games.

From the top of my head


neverwinter nights
Baldur's gate 1+2
Duke Nukem 3D
Commandos 2 (I think it can be played via lan)
Flatout
HoMMs
Painkiller
Patrician 3
Soldiers Heroes of WW2
Unreal Tournaments

I think the Spellforces can be played over LAN. Used to have internet based MP but the servers are dead.

Great answer! To narrow it down, which games are most enjoyable with only two players?

I actually got FlatOut on Steam and both Painkiller and Patrician 3 on GOG. So I would only have to buy one game for my brother to play them in MP. I got one Spellforce too, so just need to gift one for my brother and ask for my CD-key.

I think sacred gold can be played with hamachi or something similar

Anymore suggestions and still wondering which of the games that plays best with only two players?

HOMM3 is my fav multiplayer Gog game. I play hotseat, with a mate most Sat nights, we just sit around drinkin and playin. It's great cause it's relaxed and competitive!

Fallout: Tactics can be quite fun in LAN.

If you're into hack n' slash, try Sacred.

Get Neverwinter Nights NOW.

PS: see you on Christmas :-p

Oh I forgot to mention, I used to have immense fun playing M.A.X. with my brother with hot seat. Have a look if you're interested in turn-based strategy.
Also, not on GoG but Civ III on easier difficulties can be quite fun in multiplayer.

Not that it'll give you personal recommendations, but you can filter the category to show games with multiplayer and co-op:

http://www.gog.com/en/catalogue#all_genres/gameMode/multi-player/

http://www.gog.com/en/catalogue#all_genres/gameMode/co-op/