Terran sucks like hell

Wraiths and siege tanks are an excellent combination for terrans. Battlecruisers are overwhelmingly strong, but they're too slow and very vulterable to a few kinds of attacks. (defilers anyone?)

For Zerg, a zergling rush is devastating to most newbies, as they're good at attacking with a lot of tough units. Of course, one fun thing to do in zerg vs zerg is to build a nydus canal at the enemy's creep, and if he doesn't notice the remote building, his base will be taken out by ultralisks in no time at all.

Protoss are fun, especially when using a strategy called Photon Cannon Offense, which is based on attacking the opposing base with lots of photon cannons. One of the biggest disadvantages with the Protoss is that they really have no great defensive capability of taking down long range attackers such as Guardians, Ghosts, Siege Tanks and so on. Well, Dragoons in Brood War can do the trick, but they're mostly weak anyway.