I usually try something new every year, but my sister always asks for a cake made of melted Mars Bars which I'm always *extremely* happy to make for her
My own favorite... either red velvet with cream cheese frosting, or maybe one with pineapple (whether pineapple upside-down cake, or a regular pineapple cherry cake, or carrot cake with pineapple and cream cheese frosting.)
I love buttercream frosting and cream cheese frosting, but if a cake is topped with whipped cream, I usually won't even bother eating it. It's always such a textural disappointment.
Mouth feel is a big deal to me
(And, of course, I would eat it if somebody had made it. But nobody makes cake with whipped cream as a frosting, and I'm not going to hurt the grocery store or bakery's feelings by being true to my tongue