What's the corners / trackpad hack about? I've been using F1 to switch spaces when I don't have my Magic Mouse hooked up (and then bind middle-click to it).
Rob
I use three finger up and down swipes for expose and spaces, respectively. For that you need a hack tool like BetterTouchTool.
I have the three finger swipes on in the trackpad - but that only goes back and forth. That then allows me to add hooks into three fingers up and down... I think it's great! It's especially useful when only using a single screen - as you never lose your mouse pointer, and it makes it very easy to switch apps or screens. I was a big fan of doing this on my hackintosh....