Probably the smartest thing to do with versions of Windows is to wait for the first service pack, or the "second release". PC World points out that Windows 7 fits right into this longstanding MS trend:

Microsoft would like you to believe that Windows 7 is going to be the next great desktop operating system. It's not. The company would also like you to please forget that it said the same things about Vista. Remember how Windows 98 was followed by Windows 98 Second Edition? That's what we have here: Windows 7 is Vista SE.

If that pattern does hold up, then Windows 7 will likely be a decent OS: 98 SE was far more stable than 98. Windows 3.1 was far better than 3.0, and XP service pack 2 was far better than XP. The marketing problem that Microsoft has developed recently is that they've allowed Apple to define them by the initial release of Vista. That, and the fact that they spend way too much time hyping their releases before they are close to ready...