Broken Hill Interactive
Broken Hill Interactive use XAMMP to develop our websites on a windows platform since most of our client sites are hosted on linux servers. We also design and implement around OS CMS platforrms like Mambo, Joomla, etc.
I personally also use - audacity for my minor sound editing needs (actually for chopping and changing ring tones for my phone), PDFCreator and Ubuntu when I'm desperate for a Linux sandbox to experment with.