New PC, good Online Co-op games?

Hey guys

I'm a long time console gamer, played some games on the family PC when I was younger (15 years ago ish) and I just ordered the parts to build my first gaming PC.

I'll spare you all the details but basically it's a

Sandy Bridge i5-2500k 3.3ghz Quad Core
4GB DDR3 Ram
Radeon 6850 1gb GPU
1080p LCD

I bought a few games during the steam sale this holiday in preparation. Well, more than a few, I got a little carried away

AaaaaAAaaaAAAaaAAAAaAAAAA!!!
Plants vs. Zombies
Commander Keen Complete Pack
S.T.A.L.K.E.R. CoP + SoC
Telltale Holiday Pack
Amnesa: The Dark Descent
Crysis Complete (NA)
Doom Pack
Star Wars: KOTOR
The Witcher: Enhanced Edition
Humble Indie Bundle
Puzzle Quest
The Deus Ex Collection
Winterbottom
Super Meat Boy
Humble Indie Bundle 2 - Retail
Flight Control HD
Shatter
VVVVVV
Introversion Complete Pack - Summer 2010
Torchlight
Altitude
Portal

So I'm pretty well stocked for a while, but I have another close friend who has a nice gaming PC and we are looking for some good Co-OP games to play and I wanted to some suggestions.

Here's what we have or are thinking of so far

-Diablo 2 (already have this and played about halfway through already on my mac and plan on finishing and playing more now)

-Alien Swarm (co-op and free, looks cool so I figure why not try it out)

-Trine looks pretty cool too

I've played the shit out of borderlands, and most of the console online co-op games in the past couple years, so anything cross platform i've most likely played.

Any other good co-op games you guys can recommend? Feel free to recommend older PC games you consider must play as well. I've played all the half life games in the orange box already.

I built my first PC and bought the same graphics card but it came DOA from newegg .

Try left4dead, left4dead 2, Killing floor. I should have bought LF2 for $5 when it was on sale.

[quote name='maxim2boobles']I built my first PC and bought the same graphics card but it came DOA from newegg .

Try left4dead, left4dead 2, Killing floor. I should have bought LF2 for $5 when it was on sale.[/QUOTE]

i hope i have better luck!

played both left4dead's on console, i'll check out killing floor

Dead Rising 2 has pretty fun co-op as does the new Lara Croft game.

[quote name='mang9432']i hope i have better luck!

played both left4dead's on console, i'll check out killing floor[/QUOTE]

When they go on sale again, I'd think about buying the PC versions. Not only are the controls way better, but you get all the DLC that the Xbox versions charge for, for no extra costs!

And of course, Team Fortress 2 is pretty much the best team based shooter ever made! If you played this on your console, that contains a small fraction of what the game has become over the course of it's 150 or so updates! Even at $20, the value is incredible, but if for some insane reason you decide to wait on it, it goes on sale damn near every major Steam sale.

EDIT: Actually, if you don't have Half-Life 2 or it's expansions, The Orange Box http://store.steampowered.com/sub/469/ is still an excellent value, even if you already own Portal. Those aren't co-op games, but they are some of the best single-player games around. And you get Team Fortress 2.

Yeah i Have for xbox Dead rising 2, lara croft, left 4 dead and orange box, but I can definitely see the appeal of the L4d + tf2 on the PC instead, especially as cheap as they get sometimes.

I think i'll probably pick up them when they go on sale as i have a couple people i know who play tf2 on pc as well, I didn't like it on console but i hear it's a very different game on pc.

Heads-up on Trine, the co-op is local only (I know, it's ing stupid).

[quote name='SEH']Heads-up on Trine, the co-op is local only (I know, it's ing stupid).[/QUOTE]

oh wow... good to know. lame.

You can check out my 'Free And Legal PC Games' thread.

A good CO-OP FPS game that is on there that I can reccomend from what you have already highlighted is 'Alliance of Valiant Arms'. Outside of that you already spoken about 'Alien Swarm' which is free and on STEAM.

You can also work on setting up your PC with your TV and using some controllers from you consoles to play from your couch too. So enjoy your re-entry into the PC arena.

[quote name='JasonTerminator']When they go on sale again, I'd think about buying the PC versions. Not only are the controls way better, but you get all the DLC that the Xbox versions charge for, for no extra costs!

And of course, Team Fortress 2 is pretty much the best team based shooter ever made! If you played this on your console, that contains a small fraction of what the game has become over the course of it's 150 or so updates! Even at $20, the value is incredible, but if for some insane reason you decide to wait on it, it goes on sale damn near every major Steam sale.

EDIT: Actually, if you don't have Half-Life 2 or it's expansions, The Orange Box http://store.steampowered.com/sub/469/ is still an excellent value, even if you already own Portal. Those aren't co-op games, but they are some of the best single-player games around. And you get Team Fortress 2.[/QUOTE]

half life has tons of multiplayer mods you can download for free from steam. i was really disappointed with orange box on 360. i will give it another chance on PC.

[quote name='maxim2boobles']half life has tons of multiplayer mods you can download for free from steam. i was really disappointed with orange box on 360. i will give it another chance on PC.[/QUOTE]

Yeah and if he does not want to spend any more you can get HL2 Deathmatch for free from STEAM + you can dl CO-OP maps were you and some friends take on modded scenes from the game or other creatures the community created.