I've been using django, but I picked it because I enjoy python more than ruby. I think that they are close enough that the selection comes down to whether you've any pre-existing experience with either framework or language. If not, then I claim the decision really lies between which language you want.

My biased and un-researched opinion is that you'll find more support for learning python than ruby.

I'm leaning more towards Django currently. I've worked with Django for a longer time than RoR so that may be the source of my bias.

I prefer it because it gives me more out of the box. I can set up logins and accounts very easily for example. It is however a complete pain to install. Chances are you will spend days fighting with it and may even give up before you ever get it working!

Rails, but I can't judge Django because I haven't played with it on more than a superficial level. It seems like it really comes down to preference. I love the Ruby (and Rails) community right now and there are a lot of hopes for Ruby 1.9 as far as speed goes (supposedly an order of magnitude faster than 1.8.5).

Rails, because that's the one I started with, and it works well enough. I like Ruby, too.

Basically, Rails doesn't have defects that are bad enough that they make me want to ditch it, and it's a pretty subjective call in any case, so I'm sticking with it. Best to get on with actually creating some sites...