N-track

I've been using N-track for years for assembling my recorded tracks and performing edits, panning, and volume envelopes. It has a direct link feature to your stereo track editor such as Sound Forge or WAVOsaur, so you can do micro-editing and the track updates in N-track...cool feature.
For the price, I find N-track to be an amazing deal... I've used others such as Audition and Cakewalk, but they are resource pigs and perform overall no better than N-track; but cost a LOT more!