Since such windows ui functionality is not part of the built-in functionality for either of the products, you'll definitively want to go with DBPro - I'm unsure whether it is at all possible to extend DBC with custom plugins (well, if you have the enhancement packs you have the
call dll function, so I guess you can load up whatever you need). DBPro have some free windows gui plugins posted around this forum.
Or maybe I got your question wrong and you just want to make an GUI of your own similar to the OS' standard one? If so you can use either product; DBPro is still better in pretty much all regards though (except that I think DBC runs off DirectX 8 while DBPro requires DirectX 9, should hardly be an issue these days though).
Go with DBPro for scalability I'd say.
"Why do programmers get Halloween and Christmas mixed up?" Because Oct(31) = Dec(25)