Thanks, I "hear" him that way myself. I always visualize him as being a very big guy, tall and broad (well, at least when he's not being starved in prison or on the run eating rats)with big gestures and voice, a nice contrast to Severus who's more reserved.

And yes, my reasons are pretty much the same. Both these characters ended in such very depressing ways and lived pretty joyless lives. I want them to be able to smile even if canon didn't give them much chance to.