I actually recommend binding it to something other than Alt (I usually do winkey), since several programs (and in particular browsers) use Alt+drag to allow you

I actually recommend binding it to something other than Alt (I usually do winkey), since several programs (and in particular browsers) use Alt+drag to allow you to select text that is otherwise unselectable. For example if you drag a link it "drags" the URL allowing you to paste it into other windows, but if you Alt+drag you can select the link text (or parts of it) for copying.