What is a good game for my boyfriend and I to play cooperatively online?

My boyfriend and I are in our 20s/30s and are looking for a fun game to play together. Preferably it is available online for Macs, or we have a PS3 as well. I would prefer a game we play cooperatively together, rather than against one another. He is a seasoned gamer, my favorite game is Plants vs. Zombies from PopCap.|||Little Big Planet is a huge hit. You can make you're own Sack boy or girl and go through a huge platforming world. They have preset made levels, and players can make their own that can be put online which makes it a game that never stops having new levels. And you can play co-op up to 4 people.|||Get shooting games in PS3, something like gear of war . Cooperative game. Need to stay together to survive. If PS3 has gear of war, my suggestion is to try that game. it was very fun for me and my friend.|||http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem%26amp;item=260503775796%26amp;ssPageName=STRK:MESELX:IT|||not relle good games for pc or ps3 but i recomed you getting a wii and playing the sports games.|||Pimps at war. See who can be the better pimp.|||For the ps3 LittleBigPlanet could be good.|||Might wanna try Modern Warfare 2 its suppose to have a pretty good co-op campaign|||TRY COMBAT ARMS ITS A FPS ONLINE MULTIPLAYER GAME ITS VERY COOL!!!|||Try Uncharted 2, that game is the ******* bees knees I tell you old chap.|||World of Warcraft!!!!!!!!!!!!!!!!!!!!!!|||Hide and Seek.|||LEFT 4 DEAD|||try some MMos|||I'm not too sure BUT DO NOT DO WOW.