I've been using TextMate for Ruby on Rails development for over a month now. One thing I missed from some Java IDEs was documentation popup. With TextMate, you can hit control-H on a symbol and the Ruby bundle will use `ri` to try to find it. Sometimes it works, sometimes not. However, Ruby gems (such as Rails) are not processed for use by ri. To do that, you have to do it manually. I performed the following this task with just one command on the terminal:
rdoc --ri-site /usr/local/lib/ruby/gems/1.8/gems/act*/lib
The '*' will expand to all of the active... action... stuff that is for rails. Once this completes (which will take a few minutes), you can finally use control-H for rails related classes and methods and get quick access to documentation. Sweet!
Oh, for some caveats on this technique, check out this URL: http://www.codecomments.com/archive327-2005-5-510886.html So basically this technique isn't perfect but it's better than before.
~ Dave Smiley