What's your favorite freeware?

I wrote today about several fantastic computer programs that are available for free to users who don't want to pony up for big-name software such as Microsoft Office, Photoshop, Audition and Norton. And, frankly, with similar programs such as OpenOffice.org, GIMP, Audacity and Avast!, you're not only saving money but you're getting something as fully featured and as powerful as the bigger-known names.