I have a pair of Lowe Alpine 'technical briefs' that work v nicely under running tights:
http://www.nevisport.com/storedetail...duct_id-275061
Re. shorts, my issue is regarding the retention of sweat or rainwater: I'm a heavy sweater and find some shorts retain the fluid more and cling uncomfortably to the upper thigh. Likewise they get v cold by retaining rainwater in the winter.
I think the only way to avoid this is to go the minimal, 80s footballer way ... though would be interested to hear of any 'dry-knit' shorts out there ...