Just check out each one and pick the one you feel has the best fit for your coding style. A properly-built site will separate the coding from the style, so it won't really matter what's underneath.
The docs are awesome, and it's getting momentum. It's simple to get started(the admin feature provides you free CRUD), runs on sqlite that's bundled with python >2.5 and it's written in Python :-)
http://snook.ca/archives/php/codeigniter_vs_cakephp/
If you want a bit of templating functionality without using an entire framework, I sometimes use a less-well-known PHP templating system called Smarty (http://www.smarty.net), which is very easy to get the hang of, and it's just as fast as using pure PHP (because Smarty actually converts your templates to plain PHP code).