$1000 seems like quite a large budget for the purpose of just doing video playback, do you intend to run other tasks on the system?
If just for video playback, I would suggest possibly getting something cheap and integrated like a celeron intel NUC/Gigabyte Brix/Zotac ZBox's and call it a day. Get the versions that can keep a 2.5" HDD in the case and you'll be able to store your video collection on it as well.
Ubuntu 14.04 LTS was just released and it's free, get XBMC installed on it and you'll have a simple HTPC ready to go.