I must say that I am not a crotch-checker-outter (after the face, I usually notice arms/biceps next), but our recent experience on the nude beach in Spain made it difficult for me to avert my eyes from the bare naked crotches all around me. I think I prefer clothing on those crotches, over all, if they're going to be meeting me at eye level (other than my husband, whose dick looks good in any circumstance)
but again, I pretty much try to avoid looking down there on most men in general.