As a frequent downloads reviewer for PC World, I look at lots of downloadable software every year -- more apps than I care to count. As a result, each week, I encounter and test-drive the great, the not-so-great, and the feeble.

Every once in a while, a piece of software so clearly outclasses its peers that it deserves special commendation. For this article, I've assembled my 15 favorite downloads of 2007, selected from a wide range of categories--everything from antivirus and security tools to system tweakers, from media managers to system speedups.

Among them you'll probably find some old favorites, but also plenty of unfamiliar apps that you'll grow to love.

Process Explorer

Do you really know what's running right now on your PC? In all likelihood the answer is no. Dozens of processes or services may run in the background without your being aware of it. And though it can show you what's running, Windows' Task Manager is a poor tool for digging deeper than that.

Process Explorer (a free download) provides exceptionally detailed information about every process and service, as well as identifying any applications associated with them. In Task Manager, you have no idea what each process and service do. But because Process Explorer often shows applications associated with each process and service, you'll be able to tell whether shutting them down is safe. The tool can also uncover clues indicating that a service or process may be spyware or malware.

Avast Anti-Virus Home Edition

These days, most antivirus programs come as part of an expensive, bloated, RAM-hungry suite that sucks up system resources, slows your system to a crawl, and requires you to pay for a new subscription every year. If you're tired of paying through the nose for antivirus protection, and want a slim, svelte anti-virus tool that does everything that high-price software does, get Avast Anti-Virus Home Edition. It has everything you need in an antivirus tool--notably live protection to ensure that you don't get infected in the first place. It also protects against instant messenger viruses, e-mail- and Web-mail-borne viruses, and viruses spread through peer-to-peer file sharing programs. It also scans your system for viruses, and eliminates any it finds.

Avast Anti-Virus Home Edition is free and extremely customizable: You can change the level of protection that any of its individual shields provides from normal to high, or create your own customized rules. So ask yourself, do you really need your current, high-priced suite?

SnagIt

If you need to capture or annotate screens for any reason--and who doesn't?--you need this program. It's simply the best screen-capture app you'll find anywhere. With SnagIt you can capture entire screens, portions of screens, active windows, menus, or scrolling screens. Or use its built-in timer to capture screens after a given amount of time. Grab screens with the cursor visible, or eliminate the cursor. And save your capture in any major graphics format. On top of all that, you can print the captured image, send it via e-mail, send it via an instant messenger program, and more.

Want to add special effects to your capture? SnagIt can do that as well, automatically adding drop shadows, watermarks, and many other effects as you direct. The program also has a very good editor for annotating screen shots, and an image browser for looking through graphics on your PC.

WinPatrol 2007

Want to rid your PC of unnecessary programs that run on startup, and help keep it free of spyware and other forms of malware? How about doing that for free--and getting other nice freebies as well, such as a cookie remover? WinPatrol 2007 delivers all that and more, conveniently and intuitively.

Set up WinPatrol, and thereafter whenever a program tries to add itself to the set of apps that start up automatically when Windows boots, you get an alert that invites you to block interloper. Click WinPatrol's Startup Programs tab, and you'll see a detailed list of every program that your PC automatically launches at system startup--including the app's manufacturer, the date the app was added to the startup set, and its file name. A clever feature called Delayed Start lets you tell certain programs to delay launching for up to an hour after Windows boots, so Windows can start up quickly and the program can still load later on. You also get a list of all the Internet Explorer add-ins currently running, along with the ability to remove any you don't want to keep.

Flock

If you enjoy social networking sites and believe that the Web is as much about connecting to other people as about connecting to Web sites, this browser for you. It's particularly useful if you participate in multiple social networks, such as Twitter and Facebook. In a left-hand pane, it lists friends from all of your social networks, so you can quickly see any changed information about them--an updated profile, say. You may also share media and Web content with them.

In addition, it displays photo and multimedia content from sites like YouTube and Flickr in a kind of scrollable filmstrip. Grab any photo or multimedia media thumbnail with your mouse, drag it to a friend's profile on the left-hand pane, and they'll be able to see it.

Increasingly, businesses are using social networking sites; if you find that work is drawing you to use such sites--even if you have no interest in them as leisure-time destinations--you may want to make Flock your browser of choice.

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