I have been trying to get my Dell 2408 working in clamshell mode without any success. I have a USB keyboard, USB mouse, power adapter and monitor via DVI plugged in. I switch the display type to mirror, close the lid, wait for it to sleep, then wake it again by pressing a key on the keyboard. The computer wakes, the external monitor flashes but at the incorrect resolution (1200 X 800 instead of 1920 X 1200) then goes back to sleep. This will repeat over and over again until I open the lid of the macbook. I can occasionally get the macbook to wake and display on the external monitor but this is very rare, and when it does I get some wired artifacts. What's really puzzling is that the monitor works flawlessly in extended desktop mode, and works perfectly with other non mac computers. I took the macbook to the Genius Bar, hooked it up to the apple cinema displays and i didn't get the same problem! Grrr.... So I just don't get it, both the computer and display seemingly work fine independently from one another, work fine in extended mode, yet in clamshell mode have some fairly major issues. Anyone have any ideas? Anyone successfully using a dell 2408 with their macbook?