What can I do to secure data on my desktop computer against the risk of being stolen?
Use disk encryption and make off-site backups
If you don't have an edition of Windows-7 that includes disk encryption, you can download and install something like TrueCrypt or any of the many commercial equivalents.
Get a hard drive docking bay, then pull the drive when you take off. That way you don't need to worry about what to sync since you have the entire drive with you.