Tough one because there are so many. My two favourite choices would have to be brownies and millionaire's cheesecake. If I had to choose something that I had to only eat as a dessert for the rest of my life, I would probably go with brownies.
This dessert has the right amount of creaminess and sweetness and doesn't take long to make at all. My husband said he didn't like it the first time I made it but then the second time he ate almost the entire pan!
I would say cheesecake, but sometimes just good old vanilla frosting on chocolate cake will do! Anyway, other treats are lemon and chocolate pie and Russian tea-cakes. Anyway, I can't really say what's my favorite.