Black tights with black shorts over the top. This comes in handy when it is cold on the ride in but warmer on the ride home. Once you get a routine down, you won't forget underwear. I have a small mental packing list that I use each day and as I pack my clothes for the day the underwear is simply the first thing I grab. It gets rolled up inside my undershirt which then gets rolled inside my scrub pants and then scrub shirt. Repeat daily and you will be fine.