Here are the 20 Vista behaviors and functionalities that could turn off Windows users. Windows newbies may not mind some of these things, but they will definitely try the patience of the millions of Windows users who've got real experience and muscle memory invested in Microsoft's desktop operating system.

20. Minimum video system requirements are more like maximum.

Microsoft's recently announced minimum system requirements aren't so minimal when it comes to video memory. According to Microsoft, the next version of Windows requires 128MB of video memory in order for the up-level Aero Glass features to take effect. As the owner of two expensive Lenovo notebook PCs with 64MB of video RAM, that have supported Aero in the Vista betas just fine so far, I can't help but be a little skeptical about that minimum system requirement.

This issue is magnified by lackluster sales of desktop PCs in recent years and the precipitous rise in sales of notebooks PCs, most of which don't have upgradable video. That means that in order to get Aero, you may well have to buy a whole new notebook PC. Although it may go against their grain from a short-term sales perspective, notebook PC makers that offer a way to upgrade video RAM or graphics cards are likely to be hugely preferred in years to come. With notebooks becoming the primary form factor in many companies and homes, the artificially short half-lives of these computers need to be lengthened.

In a private meeting at WinHEC, I asked ATI execs and engineers whether the 128MB video requirement for Aero was realistic. While acknowledging that Microsoft's system requirements are good for ATI from a sales perspective, they supported Microsoft's requirement because as the number of simultaneously open program windows climbs, they've seen Vista Aero bog down in 64MB of video RAM. While some systems might get away with it, others wouldn't.