Linux audio tools

Ok, maybe I'm having a blonde moment here - but I can't seem to google my way to anything useful. I'm looking for a Linux app, equivalent in most ways to CoolEdit. Naturally, I'm looking for it to be free. I have mhwaveedit - which does a few basic tricks, but is rather poorly designed and not quite feature-rich enough. More importantly, I'd like to be able to work with more than just wav format. Ideally, I would like it to understand wav, mp3, vox, midi and au formats - but I can convert in and out of all those easily enough, so it's not a deal breaker. Any ideas?