I've used all the above, and 2nd Cool Edit Pro (you can grab a copy off of ebay with Acid 4.0 for $100! Been listed for the last few weeks)
Another one that I use, but don't have loops or midi, is the Kristal Audio Engine
. It's free, can do 16tracks, uses VST effects and ASIO. I think it is the best free audio app out there, and combine it with Audacity or the Sound Engine Free wave editors you can have a FREE setup to get your feet wet with. With ASIO4ALL
or the kx project drivers you can get some really low latency.
It has occurred to me that there are fewer years ahead than there are behind....