I have been wanting to try Linux for a while and finally took the plunge after some prodding from a co-worker. He knew that I had been in bands and recorded music so he pointed me towards some programs I might like.
Ubuntu Studio seems to the the Flavor of choice as it comes with several programs already loaded and ready to go but there are several other flavors as well like 64 Studio.
Ardour ( http://ardour.org/ ) being the main DAW. It has been compared to being the "Pro Tools" of open source software. We shall see when I get everything up and running.
Rosegarden ( http://www.rosegardenmusic.com/ ) is an audio and MIDI sequencer, score editor, and general-purpose music composition and editing environment.
Hydrogen ( http://www.hydrogen-music.org/ ) is a drum machine for GNU/Linux that uses pattern-based drum programming. ( I have played with this one a bit and its not too bad.)
some useful links off the top of my head would be :
http://www.joebutton.co.uk/fst/ (VST plugins)
The list goes on and on. As I use (or try to use) these programs I'll post here and let everyone know how its going.