I started off gaming (as far as i can remember and except the childs games i played when i was 5 or so lol), when i got my new computer, which must have been about 5 years ago now, shock horror! The first online game i played was Halo!!! (i used to play a lot of console games, and still do sometimes) I played halo for a while, got in a clan! Which is kind of what i'm replying about, because you said it's hard to be with the same group of people while playing a game... that's not really true if you become good enough at the game and get into a clan... I stopped playing halo for about a year i think, then i went back to it majorly and got into it again and now i'm in one of the top clans... i quit it though to move onto MMO's now ^^, i've spent enough time on FPS's.
Also, i bought Battlefield Vietnam because my first halo clan moved onto it... i didn't like it much though... it was alright but with 5 min loading times no jokes), it got to the point of stupidity, and besides it was not that fun anyway, apart from learning to fly, which took ages...
I've played tons of other FPS's, but i can never stop playing halo, it's so addictive, even when i've played the same map, literally 500-1000 times lol.
So yeah now i'm moving onto MMORPG's full time... and i just checked that guy who i said had 1000+ hours of Final Fantasy XI, and it seems he's got more than 4500 ! No joking, if anyone has xfire i'll tell you his name on it lol.
On the note of xfire though... surely someone has it here

, it's only the most needed application for gaming >.>