My trip is 7-10 miles one way. I usually wear the shorts or pants that I will wear that day (jeans/cargo pants) with a velcro strap to protect it from the chain. I'll wear long underwear if needed. My back gets so sweaty however that I always wear a microfiber/poly t-shirt and layer on top of that as needed. Today I wore a long sleeve poly shirt, a vest and a bright yellow windbreaker (darn daylight savings time moved my commute into the dark). At work, I'll sit 5 minutes then change into a polo shirt.