In the past I did some sound editing for bands or theatre, but in more recent years I've been doing more video editing. Because of this I now use Adobe Audition as it's part of Adobe Creative Suite. I know Adobe software is expensive, but a lot of people are eligible for it at a fraction of the cost, via Adobe's Education Resources. An example In the UK, is anyone with a child of any age at school can get most of the software totally legally at massive reductions. Not that I'm trying to sell it at all.
Sound editing stuff I've used in the past has included; Cubase - long time ago and okay for musicians, but I didn't like it. Cakewalk Sonar - great for multi-tracking and lots of good features. Cool Edit Pro - loved the waveform features and great effects for enhancing sound. And it was Cool Edit Pro that Adobe purchased to enhance it's Creative Suite as Adobe Audition. Now though it's much more powerful, but in my opinion just as good.
As I have already said I use the video editing most and Audition to enhance the sound on that as required, but not often. As a result, if any of my info is wrong please correct me. I'm happy to learn and receive tips too. Audition is quite powerful, but I'll just mention a few of the things that I think some of you guys might be interested in.
Editing in Waveform view is great and the added Spectral view is really useful for seeing where the sounds you're interested in really are (even the frequency range they are in). The various ways of altering volume are quite sophisticated, but take some experimentation and time. The noise reduction is supposed to be much improved in the most recent version, as advanced parameters have now been added, but I haven't had chance to play with them much yet. It's supposed to reduce that warbling and tinny effect that a lot of noise reduction creates. Another factor I find useful for basic enhancement is the 30 band equaliser. A final little bonus that might be of interest, is the various number of formats you can save files to, so it can be used as a converter as well.
To keep it simple, the way I tend to work when trying to enhance sound is to cut out any peaks and deal with amplitude first, but leave space for other effects to avoid extra distortion. After that I use noise reduction, but lighter rather than heavier and finally finish with a few tweaks using the equaliser. It's not magic and it never will be, but it certainly helps.
I better mention what can be a big downside for a lot of guys. It will work with older comps, but some of the processes take a long time and I do mean long. So applying, listening and tweaking can be a bit tedious to say the least. With a fast computer though, there's not much waiting if the file's not massive.
I'd love to hear from anyone with suggestions for better ways of sound enhancement, or tips, or comments on software and opinions of it.