The Sigma 24mm f2.8 Macro Super Wide II is a real sleeper. Very affordable and got a whopping 4.0 photodo score. KEH has it for $49 right now.
The only problem is I believe the A2E is one of the very few models which can't control the lens properly. I use it on a cheap, lightweight EOS 300/Rebel 2000 body (you can get these for ~ $10). The reason the price is so low for such an excellent wide angle lens is that it won't work correctly on digital either.