I'm a "CS Nerd" :P.
Actually the term is Mil-sim or woodsball. I guess you could call it the direct opposite of speedball. Sure it's a tad nerdy, but I think it makes more sense to run around the woods in camo versus brightly colored speedball jerseys. I've also served in the CF Reserves so I like the tactical style play much better.
Though I do think that the bi-pods are a bit excessive as there's no such thing as a sniper marker.
Myself, I'm running a B5 marker kit from these guys:
http://www.identitycrisispaintball.com/. It basically takes a stock Tippman A5 and uses most of the internal parts, some of the chassis and turns it into a bullpup type assault weapon.
Here are a couple youtube vids... not me, but of the marker in action.
In combat:
http://www.youtube.com/watch?v=pE0ZcUOk5D0
This one sounds the most like my marker:
http://www.youtube.com/watch?v=aUJGP...eature=related. I'm using a J&J 14" ceramic right now and it's a bit too quiet for my liking.