Couple of things. I'm all for gun rights, for starters, even though I don't own a gun and really have no intention of ever owning one. I know I'd be pissed as hell if someone told me I could no longer fish and took away my reels (I know, obscure...but just trying to compare hunting to fishing, hobbies yanno)
First off, I don't think there is anything to worry about. Obama can propose a law banning guns, but it would still have to make it through the house and Senate. I doubt it would gain much steam, and even if it did the GOP still has the ability to fillibuster and I'm sure there are more than a few Republicans willing to stand up and read two phone books if need be.
Secondly, I think Biden is probably the one you have to worry about the most in this respect. I believe he was the one that started the talks about the Brady Bill in the first place. Add to that his reaction in the CNN debate towards guns (http://www.youtube.com/watch?v=nkavwuWE5eQ
--fastforward to 1:17 for those who haven't seen).
Thirdly, I kinda want to buy one now that there is all this hype. Like I said, I don't really want one...but on the off chance this did happen, well shit...it becomes appealing.