Well, I use my powerbook as my main machine. All my development is done on this, so more power would be very nice. I know several people that have a big monitor and external keyboard. When they are home, they connect the monitor, keyboard and mouse, close the lid on the laptop and press a key on the keyboard. Voila, the powerbook uses the nice big monitor just fine and so instant desktop.
I'll take as much power as I can get in my laptop, as long as I don't also sacrifice portability and battery life beyond reason, for some value of reason.