I've always been a huge fan of clickbank analytics. Not too long ago they completely changed their layout and I think the old layout was a lot better. With the old layout i could check out gravity change in each category, organize them from highest to lowest. The new layout isn't even desirable to look at. Does anyone use a different site to check the stats?
as rolf has pointed out you can still sort by gravity change (delta) Just hover over the combo-box that contains current sorting param (to the left of page buttons) here are business to business products sorted by gravity change