XP on laptops preinstalled with Vista......
It may not be as easy to install XP on a laptop supplied with Vista as you think - at work we had some Sony Vaio laptops delivered with Vista preinstalled. We were going to wipe them to install XP but couldn't as XP wouldn't detect the hard disk in them!
Searched on Vaio link but Sony don't supply XP drivers for laptops preinstalled with Vista so couldn'y even get XP installed let alone the extra drivers!
Other manufacturers may supply drivers but its something to watch out for so be careful and make sure you have install/repair disks (with Sony Vaio's and some other brands you have to make your own) before you try to install XP.
As for my opinions of Vista - well I hated it at first but am slowly starting to get used to it. Have no desire to move off XP till I'm forced to though.
Switching off UAC definetly helps but it still has some annoying traits - copying a shortcut to the All Users desktop becomes a struggle (after you find where the all users folder is hidden if you try to copy a shortcut straight from a network drive it will fail but will work if you copy to your desktop first then from there to all users desktop).
Also it seems like Microsoft have tried too hard to make it different from XP (moving things about / changing standard pratices etc) in order to try and convince people to upgrade. As an example in XP, NT, 2000 etc you can log in to a network PC without using the mouse (Alt-U then type username, Alt-P then type password, press enter). On Vista this is a struggle as there are no keyboard shortcuts for this.
I'm just glad the powers that be at my work decided not to roll out Vista this year - wish me luck next summer!
Jay