What is the best kind of underwear to wear during yoga?

I have ordered some yoga videos and some clothing designed for yoga, however i have tried looking for a sight that would tell me what the best type of underwear is for men to wear during yoga. I know that the clothing is not supposed to be restrictive but i have also seen some yoga poses that look uncomfortable to be done with out support, please help guys.

Yoga Babe Gone Wild – 07/17/08