Yeah, I had a look at fleximusc but it's a bit tacky. One of the dozens of almost-good software packages available. In the end I went for mixcraft from acoustica which is much better than fleximusic but costs the same.

http://www.acoustica.com/mixcraft/

...as soon as I get a bit of cash I'll probably go for Adobe Audition, or else try to win it in the Videoforums competition

I currently use Cubase SX3 which is high end and overkill for most applications unless you are producing music.
Steinberg (the makers of Cubase) do have some entry level software if you are wanting something reasonably comprehensive.
Audacity is a good choice, Hyperengine AV by Arboretum systems is a free Mac programme which has worked well for me.
A good idea is to look up Versiontracker - there is an absolute treasure trove of freeware, shareware and commercial material out there if you know where to look.