I actually didn't use any frameworks (server or client). They always feel to heavy for what I'm trying to accomplish, especially php frameworks. I rolled my own MVC implementations for both the client & server. I've been thinking about porting the entire thing to Laravel + Backbone, to see if I like it better, but I haven't made any decisions yet. If I do, it will probably be a month or two before I get started.
It seems a bit ironic to use a front-end framework, but not a back-end framework. You should look at http://fuelphp.com, another alternative to Laravel and is a light weight PHP 5.3 framework.
