AV Audio Editor is a capable tool for audio editing which is focused very much on ease of use.
The program can work with a good range of file formats: MP3, MP4/ M4A, OGG, WMA APE, FLAC, AAC, MPC, SPX, TTA and WV.
Basic operations are very similar to other audio editors. Whatever file you open is presented as a waveform; you can freely zoom in and out to view and select whatever areas you need; and you might then cut, copy or paste them, adjust volume (fade in, fade out), add a few effects, and more.
The interface is well-designed and very comfortable to use. Selecting a chunk of an audio file is a key task, for instance, and here it's very straightforward. There are lots of zoom controls (both horizontal and vertical) to help you locate the area you need. Highlighting an area with the keyboard is very easy because you don't have to learn any new controls; just use the cursor keys to select the start or end point, then hold down Shift and press the cursor key again to select the rest. Or simply click and drag with the mouse as usual.
The Effects menu is a little more frustrating, because although there's a lot that looks promising - equalizer options, pseudo-surround sound etc - most of these are only available in the commercial Plus version. And these aren't highlighted, which means you're regularly selecting effects only to find out they're not available.
Version 2.02: "Multi-track editing feature now FREE and fully featured."
While it's a little short on features, AV Audio Editor supports lots of file types, and provides a comfortable and easy-to-use environment for trimming, volume tweaks and other basic edits