Hi guys, I think I can contribute some usefull stuff to this thread:
My favorite discovery in Live is that you can 'overwrite' automation keypoints by holding SHIFT while you drag one point over other points. This saves me a LOT of clicking when I need to clean up recorded automation
There's also a very good Live shortcuts image out there, but I'm not allowed to post images atm, so you just have to google for images with 'ableton shortcuts' as a query (it's the black one).
Another thing I only recently discovered is that you actually CAN collect your channels in groups. This is great for keeping your projects manageble, but even better is that you can put effects on a group as well! No more messing around with sends (I never really figured those out in Live), just slap what you want on your entire group and you're ready to go.
Btw, the AMP from the latest version of Live RULES! It can beef up any sound in a lot of cool ways. It's kind of like a distortion unit combined with a Utility and the Slayer VST fx.