You can see the wire-frames for almost all of the units of Starcraft 2, along with various achievement, decals, and cool portraits!
However my favorites are definitely the high resolution "Planet" loading splash screens, which makes for an amazing SC2 related desktop wallpaper.
Be sure to head over to SC:Legacy in the link below to check them all out in higher resolution!
Links
SC:Legacy - Starcraft II Beta Game Images
