I'm biased

But I really enjoy terran because of the way it feels so active the entire game. Zerg has a similar feel for me, which is why I enjoy offracing as them when I feel like dicking around on the EU server. But I get a certain satisfaction of having to constantly be producing units/depots/expos/ups as opposed to producign them in waves (larvae with zerg, warp gates with protoss). What sucks with terran is the complete inability to tech switch. Once you get to your late game you are probably NEVER going to switch your tech since you should be being aggressive all damn mid-late game long, and if you suddenly lose supply and have to wait the inordinate amount of time some higher supply units take to build you can straight up die. 

I gues that's what I really really like about terran: the active macro play and favor for heavy aggression.
P.S. can you tell I play bio? :P