Thanks DJ, I will have to consider everything carefully. At the moment the box will be used mainly for playing movies and series' off an HDD. I might look at Netflix or Hulu at a later stage but this is not a requirement for me. The reason I am looking to get a media center is I moved my PC from the lounge and the PC used to double up as a "media center". So I just need something to replace that. So like I said, will mainly be used to play movies, series' and sometime music (MP3) through my home theater. I will most probably be using XBMC as I am quite familiar with it.
What worries me most is the wide range of different format movies and vids I have. I just want something that can play it all

A lot of my vids are YIFY "1080" mp4's with some full HD 1080p vids (20GB+ per movie).
I am not too clued up on the Linux OS, but have some experience with it.
Thank you for the detailed reply