I stick with HB pencils and about an A4 paper size (more or less). I draw really small though so it doesn't really bother me all that much. But that's only for random sketches and crap.
Anything that requires a lot of detail is on my ginormous 18x24 inch drawing pad with my even more ginormous drawing board. 18x24 pads are used quite often. A lot of my friends use those all the time when they're not using a sketchbook.