I use SyncBack to sync my laptop and desktop with a 2TB NAS drive. It works really well. You can schedule it to run at specific intervals, or when it detects a change to any file in a specific directory.
Mine is set to sync at 3am each morning. I'm syncing my iTunes library, including video and apps, and about 8gb of photographs, and I don't ever notice it.
edit: I also really love the folder comparison thing it does. It makes it really easy to see what is backed up and what isn't.
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