I roll mine. I use a backpack so I just roll and stack, usually jeans first, then shirt, undies, hand towel.. that's it for my clothes.. When I used a messenger bag I rolled too, but instead of stacking i'd put them in vertical rolls next to each other if that makes sense.

However, being a graphic designer, wrinkles aren't an issue for me, I can pretty much get away with wearing anything as long as it doesn't stink.