What I've said about the
D&D miniatures all along is that they should concentrate on creatures that are specific to
D&D. To that end, I'd recommend:
Roper
more (and more common) Mind Flayers (those suckers are hard to find)
more (and more common) Beholders
more (and more common) Umber Hulks
more Githyanki and Githzerai
I'll second the vote for a Rust Monster
Also, in terms of things I'd like to see just 'cause I'd like 'em...
more and better Gnomes (how about a decent Gimble?)
more and better Halflings (Not so militaristic! I want 'em hobbitish, dang it!)
more personalities (we've got Drizz't and Mordenkainen, so how about Elminster? Raistlin? Iuz the Old -- both forms?)
a black-maned barbarian who isn't named Conan due to licensing issues
a grey-clad rapier-and-dagger wielding rogue who isn't named Mouser for the same reason
I'll second the vote for a Flumph

and raise you a Flail Snail!
-The Gneech
