If you're looking to speed up Vista or customize the way that it works, and are willing to pay the money to do so, Vista Smoker Pro ($30, 7-day free trial) is a solid choice. It can optimize your memory, hard disk, and overall Vista use. Compared to the earlier version of this program, the newest iteration has a much-improved interface that is slicker, and makes it much easier to use all of the program's features.
When you run the program, you get an overview of your PC's functioning, including total RAM, available RAM, used RAM, and more. You can then choose from one of four main categories of optimization: Tweaks, Maintenance, Security, and Passwords. Each of those categories has many settings you can change, and each of those settings in turn may have numerous sub-settings. All this means you can customize and tweak just about any part of Vista.
Sometimes it seems as if there's nothing too small to escape this program's notice. Want to optimize Vista for game-play? The GameBoost feature will shut down services and free up RAM and CPU cycles for you. You can optimize your CD drive, improve graphics performance, shut down services, and tweak Internet Explorer to your heart's content. For those who dislike Vista's intrusive User Account Control feature, the program will let you change its behavior. It will even let you remove arrows from shortcut icons on your desktop. There's also a good Auto Tuner feature, which will automatically do tweaks for you.
I had a few minor problems with this program; the Startup Manager, for example, didn't show me all the programs that run at startup. But overall, it worked well. One note of caution: It's a good idea to create a Restore Point before using this program, so that if anything goes awry, you can always get things back in order.
Given that there are a number of free tools that optimize Vista, you'll have to decide whether it's worth paying $30 for this program. It does give you tools that go well beyond what freebies offer--for example, no freebie offers GameBoost, and no freebie lets you make such a vast number of changes. If you're satisfied with the basics, you won't want to spend $30 for this program. But if you need to tweak every aspect of Vista, it might be for you.