I would skip anything with claws and go for the snails. Assorted snails. I picked this up somewhere along the way. . .
Nassarius Snails : Great detrivores and sand-stirrers. They will hide in the sand until feeding time.
Astrea Snails : A great algae eater, but sometimes fall off the glass onto their backs and will require a little help to right themselves.
Banded Trochus : Algae eating machines. Ideal size, won't knock over corals/rock, and can move very fast.
Stomatella Snails : Will breed in your tank! You will only need to get 4 or 5. They're great algae eaters and stay very small. I give these to all my friends. =)
Cerith Snails Will also breed in your tank. Good algae eaters and sand-stirrers.
Fighting Conchs : Little vacuum cleaners. One per 2 sq. ft. of sand. They'll eat diatoms and, sometimes, cyano
Turbo Snails : They are big and clumsy. They'll knock over or move anything that isn't glued/nailed down.