Just wanted to chime in. Running XP SP3 on MacBook Pro (10.5.5, 4GB RAM, 2.6GHz Core 2 Duo) with 1.5GB assigned to VM. I saw this problem continually. I have actually rolled back to a snapshot I took just before upgrading and reverted back to Fusion 1.1.3.
An interesting note though while I was still using 2.0... I tried the uninstall/reinstall of the tools. After uninstall, Windows of course rebooted. After this reboot, the VM window shows what appears to be only the top right corner of a much larger screen that the VM thinks I have. I am able to log in, but after that I have no visible/accessible Windows task bar. Installing the tools is quite problematic because the dialog boxes that appear (well, I assume they appear) for the install are in another area of the virtual screen that I cannot see or access. After trying this several times (revert to snapshot, upgrade VM to 2.0, uninstall tools, failed tools install), I gave up and went back to 1.1.3. Much more robust for me now, certainly not as snappy with moving large windows in Unity, but small price to pay for actual usability.