Head on over to http://eu.starcraft2.com/movies.xml#m3 and check out the new Starcraft 2 Gameplay video. The video is a whopping 21 minute description and showcase of some of the new units and abilities in Starcraft 2!
This video gives us more insight as to what new units will be featured in Starcraft2 that we did not already know about. The big flying protoss space station that looks like it was Stargate Atlantis is actually the Protoss mothership see its description here. The Protoss also have a flying unit named the phoenix which is used against light air units, while the warp ray is used against heavy units. The Terran have a new unit named the Reaver, which could be replacing the Firebats, it is able to jet pack across the terrain and used their pistols to kill Protoss Immortals.