Well the reset as described by the page I linked to doesn't affect data on the device, but if it still happens after a restart you may have a software issue which can only be addressed with a restore, which WILL affect data on the device. However, as long as your device has been backed up to your computer, after the restore has finished you'll be given the option to use a backup or set it up as new. Setting it up as new and giving it a different device name so it doesn't wipe the backup will be one way of preserving your device data and making sure that its not software related. If the issue's not there after setting it up as new you probably won't want to restore from backup because that could bring the problem back...
For iPod touch/iPhone troubleshooting, anything that persists despite a restore is something you may want to mail-in or carry-in whichever service options Apple offers in your country. And if Apple decides to repair your iPod, once its back in your hands you can choose to restore it from backup and get back all the apps you had synced with it, and the music assuming its still in your iTunes library, and your contacts, calendars, notes will still be on your computer in one way or another.