Another problem with the X40 is the lack of linux support for the Ultrabase, which I also like to use every day when I come to work, so that I don't have to plug in external keyboard, monitor, and mouse. I don't like to shut down or reboot my machine unless necessary, and the ultrabase really only works properly if the machine is booted after docking. I find that hot-docking while the machine is suspended works fairly well. The machine does not lock up and functions properly. The ultrabase ports for external monitor and keyboard work. Unfortunately none of the ultrabase USB ports work when hot-docking, so I have to plug in my external mouse to the one laptop port which luckily is not covered by the base.
Undocking is not as simple. One definitely needs to suspend (close cover) before undocking, but if this is all you do, the machine will lock up on a subsequent resume at home, if not the first one then the second. I find that stopping X and removing the USB mouse before suspending and undocking prevents this subsequent lockup. In this way, I can keep the machine running indefinitely, with no need for reboots when coming to work or going home.