I use the mouse for camera look and steering with WASD for forward/boardward and stafing. Most of the time I use tab targeting, but on occation I will click a target in certain situations.
I will use a mouse to interact with some UI elements (inventory, char sheet, quest dialogs, etc). Action bars though I always use the keyboard. I like where I can setup multiple hot bars, but will only ever show one and use the keyboard to switch between them. Have never clicked on an action bar with a mouse.
**Accidental post.**
Please delete.
I have a fairly standard mouse and the only thing that makes it unique is the fact that it is a trackball and has a scroll wheel. I typically use it for movement/navigation, camera zoom, and initial targeting. If I am healing then I also use it to facilitate scroll over macros (which are literally the best way to heal, especially if you have a bunch of instant cast spells). I rarely use my mouse to activate abilities but if/when I do it depends on the innate GCD time and usually it's only long burst cooldowns or trinkets that I activate in this way.
I like to use my mouse to look about whether it is first or third person.
I like to click on enemies, and right click them to learn more about them.
I like to click around in my spellbook/inventory.
I don't really like clicking abilities save it be ones I won't use often, like buffs.