Well whatever I go with it will be backdropped by a school of tetras, likely neons or perhaps something a bit larger. I like the idea of cory cats - I'm not opposed to having two "backdrop" species with multiple specimens of each, tied together by a single specimen of a larger "focal" species, which is what I'm trying to find with this thread. It would be preferable that the focal specimen would be out and about, but it's not absolutely imperative since the backdrop species should stay active enough. The way I've found to create a well balanced tank though is to have one focal species and no more than two backdrop species, with the backdrop species occupying seperate regions of the tank (for example, a mid-swimmer species and a bottom-dwelling fish).
As for planted or not, it will definitely be a planted tank. Not heavily, probably a large focal piece of driftwood with two or three species of plants around it's base and some moss on the branches of the wood.