Q: I can stream Netflix, HBO, YouTube, Hulu everything no problem, but when I try and watch movies I have purchased from Apple, it takes hours to watch and is always buffering.. Please help!! I am having Star Wars withdrawal

I'd recommend a reset of the ATV, router and modem...

do you download the movie and watch from homeshare or stream straight from iTunes?  you may want to consider a factory restore.

Restore your Apple TV to the factory settings - Apple Support

Those other services adapt to the connection, and YouTube is highly compressed. iTunes is fixed rate, higher quality and needs to load a portion before playback begins.

What is your current connection via speedtest.net

Make sure DNS is set to auto (settings - general - network)

If on wifi try Ethernet

To see a current status of the network get a report from istumble, netstumbler or simila. Look for signal strength, noise and nearby networks