I use Audio Hijack Pro and have for some time- it's a great little app for anything such as recording a friend of mine when she was on the radio to grabbing sound effects for my projects. I couldn't imagine not having it.

I also had bought Fission, but for whatever reason I never used it, since I typically use either pro applications such as Logic or Ableton, or I'll use Audacity for speed cutting and exporting of files. But yesterday I started using Fission, and it works great, very stable and it is fast fast fast... it only does one or two things, but it does them very well and if you are like me and you need to edit the good parts out of big audio files then Fission is your go to application. I can't believe I haven't been using it all the time.

Give Rogue Amoeba a shot!