I use a naga and a razer gamepad. I have both keymapped out on my screen and in bartender I have it configured so when I hold shift, my second action bar layout of my naga pops up with all of my shift abilities. Reason being, I'd rather have more abilities on my right thumb than compromise movement. My cooldowns for the most part are with my left hand, my emergency button CDs are my scrollwheel but rotation abilities and shift most of the time engaging mouseover versions of rotation abilities are all right thumb. I like having a clean screen, big field of view especially on classes such as FCs and hunters, smaller field of view on flag returning classes and I'm constantly switching views.
I have universal keybinds where on every toon, rotation is naga side 12, my trinket is top mouse button, my mega emergency button is scroll wheel click, and health potion macros with slight defensive mitigation as top mouse button 2. It's all to work easily across characters as I have toons of every class in various levels.
On higher level toons, my action bars look full and nice, on lower levels, they don't look as pretty.
Here's a few recent screenies from my HD.
Hunter with shift held down to display shift naga layout:
Rogue in stealth looks like this for naga 1 with no shift down:
19 druid with shift held down to show my shift naga layout:
My druid with no shift button down appears as simply gamepad + naga layout and no shift naga layout:
Healer UI with team frames on left side. Would suggest dragging closer to center:
Also the square sexy map looks betterx1000
Edit: I have a few bars visible over mouse hover... such as EFC callouts / blizz ui items such as latency check etc