I've been having varying issues with my MBP and my external monitor (Dell 2005FPW). I used to plug in the DVI and not turn on the monitor, and my MBP would be frozen on the blue transition screen, but I've since turned on the monitor before I plug in the DVI. Now sometimes when I remove the DVI while the computer's asleep it won't wake back up. Other times I'll plug in the DVI and wake the computer up and it won't wake up or it goes up in clamshell mode (MBP screen doesn't light up). My MBP pretty frequently refuses to wake up so I'll have to force shut down and restart. It seems to happen more often when I've connected an external monitor but I can't really tell -- I use my MBP w/ my Dell LCD about 80-90% of the time. By "frequently" I mean 3-4 times a week, or maybe every 8-10 wakes.