I like Entanglement (3v3). It has a random feel, sorta stringy, with lots of good chokepoints.
Razor's Edge, a small 3v3, is great for quick competitive games.
Foreign Invasion, is another good small 3v3, with the added strategy of a hidden galaxy.
I love Gateway too, a great strategy map. And ofcourse, the Huge Random Single star (5v5), is also one of my favs.
I wish we had another random 5v5 map. Possibly one where starting positions are known, so a tvb (top vs bottom) would spawn with all top 5 together, and so on...