Deselecting

You may be used to hit CTRL+D all the time, but you won't have a hard time switching over. That's because the "Unselect" will be right in front of you most of the time. You just hit it, and all your selection disappears.

You also have the option to unselect only pieces of stuff, by using the marquee remove tool.

For now, selection brush and magic wand can't unselect, but soon they'll the option to do so.