I noticed this thread on RPG.net today, which linked to a DeviantArt account brimming with D&D Next concept art (looks like the artist's actual site can be found here). A lot of it is stuff that we have already seen, but there are plenty of new things in there, too (like the yaun-ti, ogre mage, and kuo-toa).
I think a lot of it looks good, particularly the humans, elves, dwarves, and aboleth: the armor and clothing look a lot more functional, and aside from the female dwarf and maybe one of the halflings there was nary a boob-window in sight (at least on the women that looked like they were supposed to be adventuring; the sun elf gets a pass, because she is wearing a bright yellow dress).
I am disappointed that the goblin, fire giant, and halflings have not seen any changes: the goblin still looks too much like an orc for my taste, the fire giant looks bland with its flat, shiny armor, and I am still not sold on the halfling's big head and tiny feet.
Also, I think the hell hound and spectre are both pretty uninspiring, and the mind flayer looks very much unpolished. Still, these are concepts and the game is still yet a ways away, so maybe we will get some interesting, polished art down the road.