When I was packing for my first tour an experienced cycle-tourer advised me to fold my shirts 'department store' style and then roll them up. Same w/pants/shorts. Put them in a double bagged plastic bag if there is any chance of rain. If you can afford it get Axiom waterproof panniers as they're great. Fenders, lights, etc. Dozens of old threads on equipping your commuter. If you think you feel like Superman now wait until you ride to work in 10 degree weather...it's the best.