One of the new features in Ableton Live 5 is right-click context menus. I mention this feature because it seems likes a small thing and many of you might over look it (or forget to use it if you are upgrading from a previous version).
This little feature is a huge time saver. For example, the image on the left (click to see a larger view) is a snapshot of a the menu that pops up when right-click in the MIDI Note Editor. As you can see, with right-click, you can quickly change things like draw mode and grid snap making this a rapid way to say - change the grid for high-hat note entry.
I recommend as you work with Live 5, you start right- clicking on interface elements to see what handy menu's pop-up.