It certainly gives me some hope that Obama was a one-time thing. Clinton is obviously an exception, but if the Biden numbers are what we'll revert back to with an "average Democrat," that's pretty good news for the GOP.
I think Biden is probably worse than a generic democrat. Quite bluntly - he's old, has a history of failed Presidential campaigns, and is nearly as gaffe-prone as Dan Quayle.
Clinton, on the other hand, is probably running a few points better than a generic democrat. Average Clinton & Biden's results, and you're probably in the general ballpark of how a generic democrat would be performing right now.