… wherever you like! Shawn Blanc blogged on his own preferred place over the desktop to place the Dock, bottom right.
Personally I’m not sold on this, since I use my 2010’s hi-res MacBook Pro only in two ways: stand alone or in clamshell mode with a Dell U2713HM display. And in both I prefer my Dock to be placed on the left of the screen, with the auto-hide option enabled. So – as ever – YMMV