Why don't you try opening them to see what they do?
Stickies...virtual Post-Its that you can put around your Desktop.
Image Capture...software for interfacing between your computer and a digital camera or scanner. You can do a lot with just this simple program that avoids clunky software from the camera/scanner manufacturer.
iSync...allows you to synchronize information between your computer and PDAs, cell phones, etc.
Quicken...a money managing program. Create a digital checkbook to monitor your finances.
Sherlock...a sort-of search engine with channels, so you can search airline flights, or eBay, or movie listings. Not really all that useful now that Google owns the universe, but it has some nice features.
Zinio...instead of buying magazines by mail or at the newsstand, you can have them delivered in digital format. Zinio offers software that allows you to read these digital magazines.
The only way to know if you should keep them or not is for you to try them out and see if they're interesting and/or useful to you.