In the latest beta build, the character creation preview gear has been updated.

Note that the sets merely serve to show a player what a higher level character of a certain class will look like.

It's not your starting gear. Many people claim the sets are upgraded Dungeon Sets from Vanilla.

All set previews are available. The only one I skipped was Death Knight, because their set hasn't been upgraded and is identical to the one you get in-game upon death knight creation (blame lazy Blizz).

DRUID

HUNTER

MAGE

MONK

PALADIN

PRIEST

ROGUE

SHAMAN

WARLOCK

WARRIOR

Note that the backgrounds have been updated to better fit their respective races a while ago.