Your choices also depend on the lighting and substrate your tank will have, as well as how much time you're willing to put into plant maintenance. I'm not sure how familiar you are with planted tanks, but if this is your first one, you might want to see what folks in the planted tanks forum would advise for your setup if you haven't already.
My personal favorites are java fern, anubias, and cryptocoryne species. I've also had a lot of luck with water wisteria (specifically Hygrophila difformis). I'm a little lazy, and they're all low maintenance plants. I'm also a little bit cheap, so I love java fern and water wisteria because they're extremely easy to propogate at home.
The cryptocoryne can be problematic when you first try to establish them, because they don't like to have their roots disturbed. I've had more than one just up and die for no good reason right after I get it and plant it, and from what I've read/heard, even people who're great with aquatic plants sometimes have this problem, too.
Anubias can be a bit troublesome if you're not sure about the person you're purchasing them from, because if they've been kept with their stolon (some people call it a rhizome, though it technically isn't because it's not meant to be underground) covered in substrate, it will frequently rot, and the plant will die. I've had anubias that looked perfectly healthy do this, and when I opened up the stolon, found the entire inside was bastically melted and the supplier had been keeping the stolon burried like a root.