IT managers are facing a perfect storm of Windows upgrade options.

While the Windows 7 beta has garnered some of the operating system's best reviews, many IT managers happy with Windows XP are not itching to upgrade, particularly in an economic downturn.

XP is running on 71 percent of business PCs, according to a Forrester survey of 962 IT decision-makers, yet a momentum shift is slowly taking place.

Overall market share for Windows XP has dropped 10 percent in the last year, while Vista has gained the same percentage, according to Web metrics company Net Applications. Also, the same Forrester report reveals that plans for Vista deployments in enterprises are on the rise;31 percent of survey respondents said they have already begun their migrations to Windows Vista.

Time will tell if such Vista upgrade plans will be scrapped with the economy faltering, but XP users need to start planning now as they face a swirl of options: Upgrade to Vista now as a bridge to the similarly architected Windows 7; wait for Windows 7; try a mix of XP, Vista and Windows 7; stick with Windows XP and worry about upgrading later.

CIO.com caught up with Gavriella Schuster, Microsoft's Senior Director of Windows Product Management, who discussed five points that enterprises should consider when making a Windows upgrade.

(For more Windows upgrade guidance, check out the new "Windows for your Business" blog.)

Windows 2000 Headed for Dinosaur-Land

For the very few of you still running Windows 2000 (which has 1.37 percent market share, according to Net Applications), the clock is ticking.

Shops still running Windows 2000 need to upgrade as soon as possible to Windows Vista, given that extended support for Windows 2000 ends in Q2 of 2010, Schuster says.

"Windows 2000 users are going to find that may of their applications have already run out of support from their application vendors. They need to make that change if they haven't done it already," says Schuster.

If You're Moving to Vista, Keep Going

For the 31 percent of the 962 IT decision-makers from the Forrester report who are planning to migrate to Vista (and for any other Vista migrators out there) Schuster says, continue on your merry way.

"Vista migrators are in good shape; they should keep moving that way," she says. "We are setting them up to have an easier migration to Windows 7 when they want to do it because of the high degree of compatibility between the two operating systems."

Schuster also recommends that if you are in the early stages with a Vista migration, you should plan to test and deploy Windows Vista SP2, which is targeted to release to manufacturing in Q2 of 2009.