Music

If you're talking about editing/splicing/cut-n-pasting mp3s, I use Adobe Audition, which you can get a 30 day free trial of called Cool Edit, although you can't save mp3s under the trial version. One of the nice advantages to working where I work.

If you're not talking about that, I don't know what you mean by sound capturing... you mean like getting samples off of DVDs?