AppleTV Sync Problem - Hoping Someone Can Help

I have two AppleTVs... neither is successfully syncing. On both, the hard drives are very close to full. They are both set to "automatic" for syncing.

They are both synced to a Mac Pro, 10.5.6, 4 gigs of ram. I have my main iTunes library stored on a 500gb Time Capsule, which is a little more than 1/2 full.

Any new TV show I buy from the AppleTV will not download. I assume this is because the hard drive is full and syncing is not successfully occurring.

Usually what happens when they try to sync is this... in iTunes the sync icon spins next to the AppleTV listed... nothing shows in the status at the top of iTunes as syncing though, and it will spin forever. Days. It never seems to complete.

Here's the questions...

Right now, one of my appleTVs seems to be syncing (after rebooting both the AppleTV and computer). It is transferring purchases made on the Apple TV to the computer.

I have gone through all TV shows in iTunes and unchecked them... assuming this will delete them all from the AppleTVs... is that true?

Is it better to buy TV Shoes/Movies from iTunes directly rather than from the AppleTV?

If they are unchecked in the iTunes playlist, will I still have access to them, to stream on the AppleTV?

What would be your suggestions/tips for managing video content on AppleTV?

Without hacking, is there ANY way to expand the AppleTV hard drive? Is the USB Port still not functional? Does Apple offer any "official" way to expand?

Thanks!

Well, searching around some more, I think this would be the best resolution... tell me if you think I'm right.

I'll set up both AppleTVs to sync only music and photos (custom sync)... it should then stream my movies and TV. Correct?

Thanks guys...

I leave my Mac Pro running 24/7 anyway, so no problem there. I set them up to stream all video (syncing only music & photos) and it's working a LOT better now. No more sync problems. I think it was just that the hard drives were full and it was constantly trying to make room for new vs. old stuff.

I've got my library on a wireless network drive (time capsule) already, but eventually I'm going to need more space... I'll be good for now, but will probably go for the Drobo sooner or later.