Just in my experience...
I like the Zerg because they are cheap and you can make like 12-20 of them all at once, then rush. The downside to them is that they are weak
but who cares because you can raise armies out of thin air.
I like the Protoss alot, but I always seem to lose with them.
Terran? FUCK THEM. Actually I just suck terribly with them. I haven't really played anyone that can completely dominate with them either
.