The latest to arrive is the SanDisk Ultra Backup USB Flash Drive, which combines push-button backups with SanDisk's U3 smart-drive technology that allows a user to store Windows PC user preferences, profiles and settings as well as download and launch a limited number of applications from the flash drive.

The Ultra Backup USB Flash Drive (model SDCZ40-064G-A11) comes in 8GB ($49.99), 16GB ($97.99), 32GB ($166.99) and 64GB ($277.99) capacities. I tested the 32GB version and found its handy backup features quick and easy to set up. Like other SanDisk USB flash drives, this one has no cap and uses a retractable USB connector that can be drawn back into the body of the drive with the push of the thumb. I love this feature because you no longer have to worry about losing a cap and getting pocket lint in the USB connector.

I was less impressed with the flimsy feel of the drive. I couldn't figure out whether SanDisk used ultra-thin plastic for the case on purpose or if it just got a better deal from the plastic fabricator, but I was taken aback by how light this little device is. I could literally push the side of it in with pressure from my fingers. I also didn't like that the USB connector slide was slippery to the touch and a little difficult to operate.

But beyond the physical aspects of this drive, I did like its ease of use and backup functions.

The flash drive's U3 chip, manufactured by U3 LLC., in Redwood City, Calif., is compatible with Skype for VoIP, Trillian for instant messaging and Mozilla's Firefox Internet browser -- meaning that all three can be launched directly from drive itself. (SanDisk rival Lexar offers a similar application launch technology in USB drives that use its PowerToGo firmware.)

SanDisk also offers custom applications with the U3 technology for download, including YouSendIt, which allows users to send files as large as 100MB over a secure connection from any computer to any e-mail address without installing anything. If there's a network interruption, the YouSendIt U3 Application restarts a file upload where it left off once connectivity is re-established.

Set up is easy and takes under a minute. After okaying the license agreement, you click "Next" to get to an options screen that allows you to select the files you want to back up. You can select "All files" or select individual ones. By clicking on "Advanced Settings" you can select specific folders to back up by clicking on the Files tab. The Settings tab allows you to configure back-ups based on frequency (from every day to every 30 days), by date or by file size. You can back up as many as 10 versions of a file.