Stack Exchange profile: http://stackexchange.com/users/143404/teemu-leisti
Wikipedia user page: http://en.wikipedia.org/wiki/User:Teemu_Leisti
I currently use v24.3.1 of Gnu Emacs, running on Xubuntu.
I’ve used Emacs for about 20 years now. I’ve used those features that have proven useful to me, but have made no contributions to the code. I’ve found the Projectile and Tabbar packages especially useful. Projectile allows you to easily manage the files of a project using Emacs commands. This makes for enough of an IDE for Rails projects. Tabbar gives you a tabbed list of open files in a bar just above the editing are, and allows you to easily switch between files using keystrokes, such as C-PgDn and C-PgUp.
My init.el file (see TeemuLeisti-init.el) sets up and customizes these packages and other stuff. I’m pretty satisfied with the color scheme, a sort of a yellowish-tan-brown desert theme. Maybe I should extract the colors into a them?