A periodic table (free) for us college students
Actually, that would be really cool. You'd click once on the element, and it could zoom in on a pop-up menu that showed more info (atomic mass, full name, abbreviation, maybe one more simple thing) then if you clicked it again it would go to a separate screen that showed really detailed info (full electron configuration, family name, properties, maybe even some facts about it). I would probably get it even if I wouldn't need it; I like knowing stuff about the elements, mainly to show up my Dad at Jeopardy (hard to do since he's so good at them).
As a plus, on the first screen, under the table, there could be a link that would start to play the elements song. That would be funny.