Additionally, with my Inspiron, I don't have to reactivate Windows (XP) when I reinstall it -- as long as it finds Dell hardware it's good to go with zero (or as near to zero as Windows gets) faffing. For me that's a pretty compelling reason to start with Windows and add Linux as required rather than doing it the other way around.
You want to be pleased its not a Compaq Presario (Or similar)... I made some recovery DVD's when a mate got a new system (With XP Home installed) and was quite literally shocked to find it filled TWO dvd's!!! That's a 8 gig backup of a fresh XP install!!!
Obviously, the vast majority of it was the cack they pre-install... Which I sharp shifted for him!
Dabz