I'm a fan of backpacks (the EMS Creek Freak in particular). Been using it daily for over a year for everything I do. It keeps things simple - no racks or baskets means a lightweight bike and forces me to travel lightly (a good thing), meaning whatever I can fit in the backpack. I do get the sweaty back, but I shower before work and just tolerate it everywhere else I go. Works for me. I have to say I don't understand the messenger bag thing - around here, it seems like people think it's a necessity if you ride a bike.