Alternative to initial sync?

I just installed ATV Flash and hooked up a 1TB external USB HD to my 40gig Take 2 atv.

I’d like to have all of my itunes media (about 250gigs) synced to my ATV’s external drive. Transferring 210 gigs will take a very long time, even over ethernet.

I am wondering if it is possible to connect my HD to my imac via firewire and copy my entire itunes library over to the external drive and then subsequently reconnect it to my apple tv thereby avoiding the need to sync the two initially.

Unfortunately no. The AppleTV stores synced media in a fairly cryptic manner, and the only way to properly transfer iTunes media is by syncing via iTunes.