Started writing this post over a week ago, kind of lost interest, but I polished it off...
After reading a couple of posts this week arguing the corner of both Ruby on Rails and Symfony, I found myself thinking about which framework I like the most. I came to the conclusion that I don't really have a favourite, just the one I'm currently using. I've used the two previously mentioned frameworks, CakePHP a long time ago and more recently the Zend Framework. I like them all. They all do similar things, sometimes in different ways, but having spent a lot of time maintaining and developing 'frameworkless' sites, I think they're all mega. Admittedly, my PHP is far stronger than my Ruby, so I steer towards the PHP ones, but that has nothing to do with the frameworks themselves.
Anyway, this lead me to have a little look on Google Trends, to see how many people are searching for what on the framework front, I included the previously mentioned four and Django, which is very popular, but my Python is worse than my Ruby, so I've not used it. I know this is hardly conclusive, but it was worth a look.
The results are pretty much what I expected. Django looks like it's a more common search term, but is starting to rise recently. Zend, CakePHP and Symfony are all slowly on the up, whereas Rails clearly had a big boom over the previous two years and is now settling down a bit.