I’m digging Rails too. And even if you are firmly entrenched in CodeIgniter land it is a good idea to learn other languages. I believe Ruby has made me a better coder and it is a great distraction from my “day work.” There are also a lot of great ways of doing things coming out of the Ruby world.
CodeIgniter/ExpressionEngine pays the bills for me though. I actually develop in ExpressionEngine during the day. ExpressionEngine gives clients a platform for standardization and support that you arguably can’t get with hand rolled solutions as easily and certainly not at the same cost (that is a subject for a different thread though.) Also, there is no way that I would want to deal with fighting clients on hosting with Ruby (PHP is bad enough.)
My personal projects are being done mostly in Rails. That doesn’t mean I can’t still use CodeIgniter along with Rails though. I have been playing with using Ruby to setup a central system which can talk to CodeIgniter “children” via XML-RPC. Kind of like what Elliot talks about in an old blog post.
Mostly just geeking out at this point. If I ever get to a point where I could pay myself to work on my own applications rather than doing client work then I might spend most of my day in Ruby.