I find it much faster to hit the off-hook button on the steering wheel and then click on a speed-dial name on the Nav screen. You only have to glance at the screen for half a second, and it takes maybe 1-2 seconds total instead of talking and waiting etc.

I also have speed dial buttons setup on my phone to just hold down "3" for example and it dials that contact, and I can feel for the buttons on my phone and not take my eyes off the road.

Thank heavens for integrated Bluetooth - California's hands-free law starts July 1st and all my friends with old phones and old cars are pissed off!