I use Yesterday's News litter, which really stops odors (unless Smudge drops a major stink bomb, in which case I'll clean the box again) and is both scoopable and light & easy to carry. And it's made out of old newspapers, so it's green too! Apparently its only drawback is that you can only find it in some places and not in others, but my nearest supermarket almost always has it, and frequently has it on sale.

Love, Columbine