How to choose a web framework?

So I have a bit of organically growing information that is nice to represent on internal web pages in a semi-organised fashion. The first iteration just runs a few python scripts from some cron jobs that utilise SimpleTAL to create staticly served pages. SimpleTAL as templating language simply because we also use roundup as issue tracker and keeping the templating language the same seems like a sensible thing to do for a multitude of reasons. But as the number of pages grows and more and more features wanting cgi, e.g. to trigger a software build instantaniously instead of waiting for the next nightly cron job, creep up this seems like the right point to move to a proper framework that will make maintenance, organisation and code reuse a lot easier.

Only, how to choose? It seems to me that the current Python web framework world changes drastically every 6 months. And really, that's just plain annoying. I don't want to worry about an upgrade of the codebase in a few months time, whether because there's a newer version of the framework or it's simply not the hip way to do stuff in the flasy web 2.0 world and hence is left to die.

Django has been in the 0.9x releases for as long as I can remember, every time I looked as some of the docs they seemed to say "Don't use the lastest release as the svn repo is a lot cooler." Not very inspiring. It also seems a pretty steep jump from the so very light weight infrastucture currently in use, it is a big (but seemingly beautiful I admit) beast.

The turbogears approach of taking best of breed applications has always attracted me. Alas that does not seem to go hand in hand with the requirement to remain stable as the 2.0 announcements seem to prove. Although they do seem to promise 1.x continuity and easy 2.0 upgrade path.

I have formed no thoughts yet about pylons other then that it can't be that bad as turbogears 2 is going to use it, but I can say that paste has a nice paragraph right on the first page:

There's really no advantage to putting new development or major rewrites in Paste, as opposed to putting them in new packages. Because of this it is planned that major new development will happen outside of Paste. This makes Paste a very stable and conservative piece of infrastructure for building on. This is the intention.

Maybe I should check out their do-it-youself-framework ...

Finally, did I mention zope just has way too much overhead? (I considered using a short script to compare all the dependencies of these packages in Debian, but it's too late at night...)

So, who in this web2.0-happy world is a stable building block for your web requirements? Seems a scary world.