+1 Commuting 25 years and have never worn anything except padded cycling shorts. In deference to modesty and good taste I've always worn some sort of loose fitting cargo or mtb shorts over top of the spandex/lycra. I've got 8 or 9 pairs of padded shorts that I change out every day. My system is to change everything to work clothes upon my arrival and the same w/t homeward leg. Depending on one's situation leaving a week's worth or everyday cartage is determained by storage availability and a suitable changing area.

My mantra is: Never commute in one's work clothes or work in one's commuting clothes. Including socks.