No, I am not an Apple hater. But I want to point out, that it is possible to turn an ubuntu into a sweet Ruby development environment – without TextMate!
The RubyBuntu series
1 – Installing Ruby (and Rails) on ubuntu
2 – Troubleshooting common Ruby ubuntu problems
3 – Be one with your command line!
4 – Make gedit better than any IDE ;)
5 – Modernize your gedit Ruby language specs!
6 – gedit 3! wtf? set it up for ruby/web development :)