After messing around with dual-head output on my laptop for a couple hours last night I decided that sticking with the laptop was not what I had in mind. Xorg released a new ATI driver that allows the dual-head to work, but it doesn't support Xinerama. That means most apps don't realize that the display is split into multiple monitors, preventing features like docking to the edge of screens from working. It also introduces new problems like the virtual screen size has to be a rectangle, so monitors with different resolutions have to scroll around the virtual space. Yuk!
So now I'm going to reinstall the desktop with Kubuntu and leave it at that.