Ed Bott, who is generally very supportive of Microsoft's products (and, based upon the products' performance, he's generally right about them), has an article about Microsoft's planned pricing for upgrades from the different flavors of Windows 7. He does an excellent job of pointing out the absurd disparities, and concluding that Microsoft's intent is to encourage Enterprise customers to continue to pay for Enterprise (rather than Anytime upgrades).

The article -and Microsoft's pricing regime- reemphasise my original conclusion: It's a good operating system, certainly better than the listless Vista, but rather pricey. Only if you absolutely need to for business should you bother to upgrade to Windows 7. At no cost (other than the minimal cost in time of migration), Home and Home-Office users can move to Ubuntu and save, save, save without losing productivity.
UPDATE: MARY-JO FOLEY JUST POSTED HER TAKE ON MICROSOFT'S PRICING FOR WINDOWS 7