So, I have just received a 1st Gen AppleTV. I love it, but have a lot of movies I share with friends and family that dont use the iTunes format. I have installed XBMC, and its pretty good, a bit fiddly, and the music/photo functionality is sluggish. Given that the only reason I want XBMC is to play other formats, am I better off installing a codec pack like Perian? Once I do that, can I still stream my films that sit on an external HD on my iMac? Or would it expect me to use iTunes somehow?