OS: Mac OS X 10.5.7
Routine Software: PS Elements 6, Bridge CS3, iPhoto '08
Less Commonly Used Software: Picasa 3, ACDSee Pro Mac Beta, the GIMP, Pixlr (web-based), GPicSync (geotagging)
Programs: Digikam and sometimes gimp. On windows I use photoshop 7.
Again, anyone with KDE 4.2 should check out the new digikam, much improved over the old version and while I still don't like the curves adjustment (cannot find a way to anchor a point but thats resolved by remembering the "x" coordinate) but there is a ton of stuff and it exports seamlessly to online gallery running on gallery2 software.
I'm not quite sure how to vote on this one as I have a Windows PC and another running Ubuntu. I use both but use Windows more often when it comes to photo PP. I use Photoshop Elements 6 on my Windows box and I find that the Windows version of Picasa works a little better. I prefer Ubuntu for other stuff.