not sure if this is the hottest but check out my signature. im hoping it is soon. i also heard about a mobile (cell phone) site that was kicking up a lot of steam. how to marketing people and mobile websites.
You can see the hottest products in ClickBank according to their gravity. in the "marketplace" do advanced search, and look for products with gravity higher than 500. you will that the current hottest products are from the E-business & E-marketing niche.
I do not go after hot products just start promoting stuff which you think are of high quality and recurring to make residual income every month sounds lovely for me.
Hottest product on clickbank is Slumdog Emillionaire , marketing on fringe, quick income blueprint etc.