2 years ago I came home from a gig and wanted to wind down by killing a few monsters on runescape only to discover that my Windows XP had succumbed to a Virus. After 2 weeks of trying to fix it an tearing my hair out I installed and started using Ubuntu linux. I have now upgraded to a version called Ubuntu Studio. This is designed for low latency Music. Video and Graphics production and offers a variety of great software for that purpose.
I had tried Cubase and It didn't work well with XP on my system. I also used Acid studio and that was better, but I had latency issues trying to mix down more that 4 tracks.
Ubuntu studio offers Ardour which is a sophisticated Multitrack music editing program comparable to Pro Tools. Using Ardour on my 8 year old Dell box I was able to mix a ten track composition using 2 or 3 plugins on each track with very little latency, far better that the software i ran in XP on the same machine.
Ubuntu Studio also offers Hydrogen, which is a great drum sequencer, Rosegarden Midi sequencer and Jack which allows connections between the different softare and Hardware resources of your computer, along with a variety of other music software.
I Highly recommend Ubuntu Studio. Also you can boot Ubuntu from a CD without installing it so you can check out the features, and it cam be installed on a Windows computer without disrupting the Windows installation (it will configure a partition on your hard drive) and offer you the choice to boot into Linux or Windows.
Check it out!
http://www.ubuntu.com/
http://ubuntustudio.org/