Fruit in beer?

[wood173]

Is there any particular rule of thumb for which beers benefit the most from an orange, lime, or whateven sliced and floating in a pint? I don't see any similarities between Corona, Blue Moon, or Dos Equis other than the fruit adding something to them. I was thinking of maybe trying some in my newest American steam-style brew. Am I breaking any cardinal beer laws?

 

[the_bird]

There's a Man Law against fruiting the beer

 

[trinitone]

There's a Man Law against fruiting the beer

Except when preventing scurvy.