With Windows Vista's release finally upon us, it's normal to wonder what Microsoft's newest operating system actually has in store for the user.

What's so great about it? What's not so swell? And what are the new features that could possibly compel me to pay up to $400 to buy it? Well, whether you're going to pay that kind of cash is a question I've dug into in another post, but if you really want the scoop on Vista's most interesting features, well, read on.

• Aero - Windows Aero (formerly/alternately known as Aero Glass) is the revamped version of the Windows GUI, a gussied up, prettified, 3D interface that's supposed to make you oooh and aaah... provided you have the hardware to run it. If you don't have a relatively recent 3D graphics card, you won't be able to run the full version of Aero and your system will default to a 2D interface which, while pretty, is not nearly as gorgeous. You'll also be able to drop "gadgets" onto your desktop: clocks, calculators, headlines, and the like.
• Integrated Search - Windows XP's dog slow built-in search is so pathetic it's a joke, and not just because of the little yellow dog that's there to "help you" find your files. Vista's upgraded search includes thumbnails, real-time indexing, and other features of third-party search tools like Yahoo! Search.
• Updated Graphics Engine - Microsoft frequently updates DirectX, the display drivers that power video games and other graphics tools. The new version for Vista, DirectX 10, is a big upgrade that fixes a number of issues (like letting you run 3D applications inside a window instead of full screen) that have long plagued the driver. Video games will get a host of new features, too, and many upcoming games will run best (with all their cool new effects) on Vista.
• Security Upgrades - The jury's out on how well Vista's new file permissions/sharing system is going to work, and what normal users might think of the lockdown of Vista from a security standpoint. Simple tasks often require multiple confirmations (a lot like how Internet Explorer now requires your permission to download files), and the OS is more complicated because of this. However the increased level of security is probably a good thing and should help prevent spyware and virus infections, at least until hackers figure out how to get around the restrictions. Parental controls are also now integrated with the OS. So far, the news on this front is encouraging.
• Updates for Laptops - As the world goes mobile, Windows is following suit. Laptops will get new power management options, and as external displays on the lids of notebooks start to appear, they'll get more features, too. Called SideShow, this is one of Vista's cooler new features, though hardware that uses SideShow may be a long time coming. (Here's a sneak peek.)
• Networking Upgrades - Wireless networking got a nice upgrade with Windows XP SP2, but Vista cleans it up even more. Newcomers to Wi-Fi should find it even easier to get online. Unfortunately file sharing between Vista and XP machines is difficult.
• Internet Explorer 7 - New browser. You can check it out now (on XP) if you're interested.
• New Backup Utility - Windows' integrated backup has been a joke for a decade. The new backup system might actually be something people will use.
• New Mail/Calendar - Improvements to Outlook Express.
• Integrated Spyware Killer - Also available for testing now.

Those are the big changes, but Vista of course offers tweaks in virtually every corner of the operating system. For more information (though biased), feel free to flip through Microsoft's marketing materials for more pictures and details.

To see if your current PC can handle Vista, run Microsoft's Vista Upgrade Advisor.

For some early thoughts on Vista, here's some commentary. (From Yahoo news)