Mine's definitely Thor - this unit looks so powerful and his concept idea just amazes me every time I see him. Besides Thor I also like Reaper, Colossus and Ultralisk.

So what is/are your favorite SC2 unit(s)?

Brood Lord of course!

Reapers and Stalkers. Yes, I really like mobility :)

I would say Stalker, because you can use it in so many ways and Ultralisk (cause it's just cool)!

I second that one. Just love the dark templars - both lore wise and in-game. :)