lol
Which is better, a bishop or a piece of delicious chocolate cake?

the bishop.. that is made of chocolate served on a chessboard!
Yes! The chessboard will also be made out of choclate cake!

I prefer the Bishop, it can move diagonally around the board. Chocolate cake I eat when I'm bored and it moves straight to my fat stomach.

Let's see:
Bishop:
Pros:
can move diagonally
Cons:
hardly edible
restricted to one colour
Choclate-cake:
Pros:
tastes well
can cover a large amount of squares
Cons:
smears when moved
So I conclude the chocolate-cake is superior.
There are some flaws here. The cake can be moved in any direction the player choose. It can go diagonal, up, down, left, right, or smeared in the opponent's face. Also, the chocolate cake is restricted to one color, unless we're talking heretical white chocolate. Any mix, such as marble cake, isn't truely chocolate cake. The real danger lies with the queen and what she might say regarding cake and peasants.
It looks like the only thing for the bishop is the fact that it's hardly edible. This would be the deciding factor if I'm playing a hungry friend and must leave for a few minutes. My cake might disapear, but the bishop won't.

I am thinking that bishop wins...
Bishop:
Pros:
Can move diagonally
Is a queen-side bishop.
Can take pieces.
Has a long-term church career, which has most-likely been hard-fought, and won, if not nessesarily holy. (The Spainish inquisition, the KKK?)
Will be preserved for the long term, as it is very fancy.
Cons:
Can be taken.
Has to participate in chess.
Is too large for it's square.
Only one square size.
Chocolate cake:
Pros:
Is larger than one square
Cannot be taken by other pieces. (It is a chocolate cake! How do you beat that?)
Cons:
Has a fork in it.
Will be eaten very shortly, so it will die.
Cannot move.
Is not a "team-player," nor is it on any side really.
Alright...
The fact that it's a queen side bishop doesn't make it superior to the cake because we don't know which side the cake is on.
I've seen chess games where someone just leaves their bishop on c1 throughout the whole game, so it doesn't really have to participate...
The cake is obviously on black's team due to it's dark color.
I tried a Bishop once - damn near broke a tooth. :(