I swear by the Assos creme...at least the old formula. I haven't tried the new stuff yet. I use it for all rides of ~90 minutes or longer, and for shorter rides if I did a long ride the day before. I apply it directly to the skin--sit bones, areas with creases, the general area towards the back that will have saddle pressure. The instruction say to apply it to the chamois but it was easier to figure out where to apply it on myself! It doesn't feel goopy, it does seem to form a protective barrier so when my chamois gets soggy on a hot ride my skin isn't equally soggy. Also seems to keep the chamois well "anchored"--I think a chamois that slips around causes more chafing. It hasn't caused any change of color in my chamois.

My favorite shorts are the Pearl Izumi Attack with the Race chamois (2007 model year with orange chamois). I tried the 2008 model and the fabric on the chamois was more slippery and the sizing of the shorts was tighter (actually all of the ladies cycling apparel seemed to get smaller for 2008). My solution was to go to the PI outlet store last October and stock up...their current year stock is full price but previous years' stock is always about 25% off; in October all Ladies stuff is (further) discounted so I got the shorts at about a 45% discount. It is kind of a thick chamois but more comfortable on long rides IMO.