Update: See my cheatsheet on Windows Vista Buying Advice for the easy answer of what you need to buy.

Have you been wondering just exactly what Window's Vista is and when to upgrade? The most detailed review I've found is from Paul Thurrott's SuperSite for Windows. Admittedly, there's a pro-windows bias here (we all have some kind of bias) and the mousemines that litter the site, waiting for you to accidentally mouse over them and launch a video are truly annoying. Still, there's plenty of good info here. Here's Paul's eight part review:

• Part 1: Introduction
• Part 2: Vista Product Editions
• Part 3: Installing Windows Vista\t
• Part 4: The Vista Experience
• Part 5: Windows Vista Features
• User Interface Features
• Security Features
• Performance Features
• Reliability Features
• Internet Features
• Bundled Applications
• Digital Media Features
• Networking Features
• Mobility Features
• Other Features
• Part 6: Compatibility
• Part 7: Where Windows Vista Fails
• Part 8: Wrapping Up

If that's too much reading for you, here's my short review: Vista is late, most of the interested features have been jettisoned, and the rest have been available in OSX or through XP add-ons for months or more, but even so, if you use Windows, it's not a matter of if you'll upgrade, but when. So, it doesn't really matter what the features are frankly. Eventually, you'll buy it.