Found this yesterday while I was looking for Portable Apps and it's very well featured.
Has the RAW filters for my Canon (plus Nikon/Panasonic and others) built in and runs on Mac/Win (32/64bit) and Ubuntu Linux.
Has a nice work space with collapsible side panels for max image space when editing. Very nice.
It's free
Has anyone else tried it?
RAWtherapee
http://rawtherapee.com/
I have included some screen shots so you can see the work space, and on the right the tools.
I use the Portable in a folder on my HDD and keep a copy on a USB that goes everywhere with me.
Trevor