More than anything you need to walk into any pastry shop here in Florence/Tuscany and take a look at what you like.
And see what Donna means by "distinctly Italian" -- which means generally puff pastry, cream, chocolate and/or fruit on top.
They are distinctly NOT any type of sponge sort of high "cake".
In general, they aren't cheap but they are VERY GOOD. So I would suggest, like Donna was, to try Marcello (it is big so have lots of options) and seeing what you like. You can get a cake custom ordered to your size within a day or two.