Counter strike:
1.6, so far the best game to play with friends on a lan party / internet cafe, old, primitive but always fun, so is Half Life deathmatch, opposing forces and deathmatch classic also Half-life deathmatch Source,
Counter Strike: Condition Zero: quite terrific games, single player missions, scenarios and so, what a ton of memories, also comes with multiplayer and local game with boots,
Source: the previous realistic game, many people claim this one as the better, i like it cuz the memories, another decent game to play with friends on lan.
CS:GO: Actually the biggest and newest game from this saga, keeps constantly updating, updating with Missions or Operations, custom weapons, gloves and so, also weapon cases and sticker ones, to customize more and more, game is pretty complete, its a shame that hackers and cheaters always come to the party, i like CSGO a lot, i highly recommend it, casual and deathmach groups are always funny, also i might advise that you will hear the most random conversations and topics at casual,
If you dont want to deal with cheaters and hackers avoid online multiplayer, that's so far the best advise i could provide.