Ask HN: What software do you use to clean audio?

If you have audio files like recorded interviews, lectures, and such, what software do you use to clean them up?

Years back, I tried out Adobe Audition, which - abstruse interface aside - did a great job. But has anything better with a simpler interface come along since?

I'd imagine there's a simple drag-and-drop app for OS X out there, but I don't really know what the best place to do the research for this is. If I had the technical knowledge to make such an app, I definitely would, because I keep encountering interviews that are barely audible, even from prolific podcasters.

I have to assume that there's software out there for people with little to no technological proficiency who just want to clean up their audio files.

Are there any good alternatives out there? What do you use?