I absolutely love cheesecake. Red velvet is good too, and carrot cake with cream cheese icing. I agree that store bought icing can be too sweet, but homemade can be really good. I came up with a recipe using sour cream that is really creamy and not overly sweet.
My family had a birthday tradition of having a chocolate angel food cake with strawberries. That was pretty good, and I kind of miss it. It was my grandma that used to make it, and she doesn't really cook anymore.