Forget limited-feature bundled apps or the now-defunct Pro
Tools Free; Mackie's got your free general-purpose audio tool right
here. Traktion
is available free for a limited time, and rivals the flagship
audio/MIDI workstations for functionality, with audio and MIDI
recording and editing, VST plugin and instrument hosting and ReWire
support, a built-in sampler and filters, and pro-level mastering tools,
collaboration, and project management. Best of all, it does all this in
a single-window interface vaguely reminiscent of Ableton Live, so it's
a lot easier to approach than apps like Apple Logic.

Give it a try via the free promotion page (registration is all you need).

What? You've already got Traktion? Version 2.0 is expected in January, and unlike the free downloaders, you'll get a discount.