Using pics, not avrs... but as mentioned before: in the end it's about complexity and how good you know the chips..
I'm a sucker for pic10 and pic12: really small footprints if needed, sub uA sleep current, advanced peripherals so that most time the only thing that the core actually do is move registers around and check flags. Same applies to dspics, when i need to do some math
why do i need 32 bits for that? you can use a ferrari to go from point a to point b, but it might be 10 meters away so you could just walk.