Are you in same mood as me and do not want to push Vista into your corporate environment? Do not matter for what reason which might be higher hw needs of Vista, reliability and proveness of Windows XP, better hw compatibility, lazy to trash deployment images of XP and make new for Vista, expectable higher demand for enduser OS support of kind “where is that button” 🙂 or whatever.
Then you should know that MS is going to cut XP sales to OEM very soon. As written here “Direct OEM and Retail License Availability (end date)” will end on June 30, 2008. So it mean if you’ll want to stay with xp after that date you’ll have to have volume licence (e.g. OLP start at 5 licences), buy Vista Business or Ultimate to be able to downgrade to XP (not sure if MS will allow this after the DATE.)
“Still, vendors such as Dell, Hewlett-Packard, Lenovo, Fujitsu, and more recently, NEC, all offer the opportunity to downgrade to XP pro.” PCWorld
These links have good info
What is also important is how long will MS provide us with security hotfixes. More info here http://support.microsoft.com/lifecycle/?p1=3223