I run my whirlpool similar to what Sparky has, except I have that setup as my dip tube. When I recirculate, I draw water of the top of the kettle and shoot it through the dip tube. This creates a very good whirlpool for me.
EDIT: The theory behind my design is two fold...
1) I seem to get a better whirlpool by spinning the bottom, perhaps because of fluid momentum or the viscus tenancies of the wort.
2) After I whirlpool, I let the wort sit and settle for 20 minutes to let a trub cone form. Then, when I drain my kettle, my dip tube is already angled against the edge of the kettle away from the hop cone. This way I don't need an external siphon to avoid the trub.