A week ago I got myself a brand new 22" LCD monitor to replace my tired 19" CRT. Both were used as a second monitor plugged in to my laptop. Given the bulk of the 19" CRT, I had it to the right of my laptop. This worked nicely for a number of years.
With the 22" LCD, and given it's widescreen aspect, I decided to try to position it above my laptop monitor. This worked nicely until I rebooted my computer.
The problem is with Vista - every time I start it up, it resets the location of my monitor in the screen properties dialog to instead be to the right of my laptop. I have to manually change this on every boot, which quickly becomes annoying.
There is much discussion online regarding this issue, and to be frank, I can't believe that Microsoft let this slip through. I seriously hope it is fixed in Vista SP1, or else I will certainly be considering my future relationship with Vista.
This is a warning to dual monitor users who are considering not using the 'Microsoft Preferred' screen layout.