I finally got around to learning how to use the JACK Audio Connection Kit, which, as far as I'm concerned, is easily a contender against the big names like Pro Audio, Cubase, or any sound program by Adobe. Sadly, Audacity doesn't cooperate with the virtual patch panel, but the Ardour DAW seems to fill in the gaps quite nicely. Combine this with Jack Rack (a tool to integrate various sound filters into the patch panel) and Jamin (a audio mastering interface), and there's a nigh-professional sound editing system at my fingertips. And if I need to do some post-processing, well, Audacity will fit the bill quite nicely.
I could use this to produce some interesting things; I have had some recent interest in performing audio theatre podcasts, perhaps do some voice-over work in the longer-term future... who knows?
Jack Audio Connection Kit
Audacity Sound Editor
Ardour Digital Audio Workstation
Jack Rack Audio Effects Toolkit
Jamin Audio Mastering Interface