Okay, the downside of a 2GB USB stick is that it takes quite a while to completely backup the files to a hard drive. And while the Travel Drive I have seems reliable, I've had USB sticks corrupt files before, so not doing a backup isn't an option.
So I went looking for software that would keep the USB stick and the hard drive synchronized, by copying over only those files that have changed. What I found was Allway Sync, at http://allwaysync.com/.
Allway Sync will manage changes to files in both directions, so if you forget to synchronize and update files on the hard disk, you can still update the hard disk with changes from the usb stick and vice versa to get them in sync again. Obviously, it can't know what to do if you've changed the same file on both the USB stick and the hard drive, so it may just let you know that it's found a problem.
But if you use the hard disk solely as a backup for the USB stick, then it becomes extremely easy to just run Allway Sync now and then to quickly update the hard disk from the stick. The product even makes sure that files you delete from the USB stick get deleted from the hard disk.
It's still not a quick process, since Allway Sync has to do some analysis of the differences between files, but it's much quicker than a straight copy of everything on my 2GB USB stick.