Buy a Vista-capable PC today and get an upgrade when Vista hits the shelves in the new year. The manufacturers currently taking part in this offer are:
From the looks of it they are all offering the same upgrade paths but different prices, and from a quick scan it looks like if you buy XP Professional with your new PC you should be entitled to a free upgrade to Vista Business and if you have bought a copy of XP Media Center you get an upgrade to Vista Home Premium.
It looks like there will be a cost to upgrading from XP Home to Vista however. The only manufacturers who are brave enough to publish prices are Sony, who are quoting a $45 upgrade from XP Home to Vista Home Basic, and $75 from XP Home to Vista Home Premium. Although their website looks like it's been put together in a bit of a rush!
Toshiba are keenly eyeing up the competition upgrade paths before they make their move and they have yet to create a web page for their upgrade offers, but I'm sure they'll rectify that situation post-haste. Could this be a case of the tortoise and the hare?
My personal view is that XP Pro users should get a choice to upgrade to either Vista Business or Vista Home Premium - because there are plenty of home users out there who have got XP Pro on their machines. I'm going to ask some internal people about this decision and then let you know the rationale behind it.