I have a Logitech mouse and love it. Button 4, and 5 on thumb side is used for 2 most used spells/actions (main attack sequence and quick react attack). I use the sideways button action on the scroll wheel for my IWT. It is simple to get to, to spam and works great.

For looting with my alts, I set up SHIFT-1 to be my 1st alt, through SHIFT-4 to be my 4th alt and SHIFT-5 to be my everyone IWT (loot). It makes it easy to do collection quests (on mob bodies).