What OS?
OS X with WinXP in Parallels. Looking to install Linux (in Parallels) at some point. Probably Ubuntu.
What IDE or editor?
IntelliJ IDEA and gvim
What backend language, if any (php, asp, cf, ruby, java, etc)?
Java!
What framework, if any (cake, symfony, rails, struts, etc)?
VRaptor (http://vraptor.org/). Used to use WebWork2.
Any other significant components (persistence layer, database, etc)?
MySQL database, Apache Torque for persistence, Freemarker for view rendering, Lucene for indexing. --Erik
