IMHO think it all depends on the type;
For instance, the taildragger i fly you have to land it all 3 at once b/c the prop is just that little bit to low that if you wheeled it on like a spit; you would have a very hig risk of dinking the prop and nosing over - esp. with not so exprience pilots. I crab it in and kick off the drift in crosswinds as someone else previously mentioned.
Heres one - how do people with a Europa with mono wheel and tailwheel config. land?