A Sheep-DAW staple must be Audacity. It's your regular WAV editor and it's as open source as they come. Audacity supports VST plug-ins and has a bucketload of built-in effects of variable quality and usability. The mild-mannered open source community provides the informal support every software user should feel confortable with in our dear post-modernity. Audacity converts to-and-fro wav, mp3 and ogg (you'll need to get the lame enconder somewhere else, obviously).
It's spartan no-bullshit GUI is intuitive and has just what you need. I wouldn't recommend translated versions, though. In the portuguese one it seems like they google-translated the terms and it's simply more confusing than the english original for pretty much everyone (yep, that bad). The looping function is a bit dumb and won't update de loop's left and right locators position sound-wise, if you move them - you'll have to stop playback and re-start, wich bums me out a bit. Another programming flaw (at least in my version) is the window management: it's one Audacity window for one Audacity project and/or wav file, so you can't really close a project file without exiting the program. Although there's a close option in the file menu, it's really an exit. It's a bit crappy when you're working on several files in one go and you have RAM restricitions, so no batch processing. And that's pretty much it, in the cons department.
In the pros, it's free, it's legal, you can (and should) share it, and besides the cons, I never needed any other wav editor.