For me it depends on the type of riding. If I'm just out and about on 10 miles worth of errands I'll wear jeans or cargo shorts, nothing special underneath. For easy/social rides up to 20 miles in nice weather I'll wear plain baggy shorts or a cutoff pair of Dickies work pants made into knicks. Beyond that I'm usually heading right for the bibs, nothing underneath and nothing else over top unless it's pouring or cold, and then I have rain/wind pants.