Hi, I'm going to buy a 27" imac [prob low end model], that I'm going to put in my bedroom and stream to an apple tv in the lounge [haven't bought apple tv yet, but I bought an airport extreme a few months ago]. I have a fairly large media collection, and I need a little advice from anyone in similar circumstances concerning streaming and external hd options. My media collection consists of about 700 cds [which I plan on ripping into apple lossless], 40 GB of concert bootlegs, 30 GB of ios apps, 2,000 photos [which I plan on scanning at high quality], and 450 DVDs [that I want to convert to high quality digital copies]. My estimate is that this will take up around 2TB, but realistically with dvds and cds being so cheap these days, I'll probably need the imac to accommodate 3-5 TB over its lifespan. I'm reluctant to get my imac upgraded to 2TB, because there are no apple stores in my country, and I don't have confidence in the authorized retailers to open up my machine [they seem a bit clueless]. And now with the news that Apple have made it harder to swap out hd's I really don't want anyone messing with my machine. So I'm thinking about getting the standard 1TB model, and a large external hd [possibly thunderbolt when they come out], and leaving it permanently plugged into the imac. I've only ever used external hds for backup, so I have a few questions about using them on a more permanent basis. 1) should I expect delays or problems streaming movie files from an external plugged into my imac to an apple tv in another room? In particular I'm concerned about playing music videos, since I'll probably watch them via iTunesDJ a lot, and I don't want constant lags etc every few minutes as it tries to load the next file from the external hd. 2) how have those with a similar set up found browsing large itunes / plex / xbmc libraries that are on external hds? Has it run smoothly, or been slow and frustrating? 3) when the hard drive dies in a few years, can I plug an external HD with OSX on it into the imac and still use it, or alternatively could I plug a mac mini or MBP into it, and use the imac as a screen? What about an external ssd with OSX on it? Would it run as fast as an internal ssd? Sorry for the long post, but I'd love to hear from anyone who has used their macs in a similar manner. Thanks!