The 2.5" drives are quite expensive, and you could get a 4TB WD RED drive for $202.99, though you will need a different case, or an adapter to mount it in the 5.25" bay, if you don't need a Bluray drive.
Also of note is that while this will handle 1080p fine, it will struggle with a video renderer like madVR (depending on the settings), which can offer better video quality.
While I understand the author is just trying to make money like everyone else, I think it would be polite to note that the links to computer parts are affiliate links.
Hanging a light on potential bias builds trust with the reader. He may have linked to the best parts, but how do I know that he didn't pick the parts that make him the most in referrals? You have to trust the author or usefulness of the information is compromised.
BTW, I'm not saying the author is taking advantage of his readers nor am I saying he has an obligation to disclose his referral links. I'm just pointing out the difference that it would make and suggesting that all bloggers consider it.
I just assume everyone in life has bias and that the links he provides my not make him much money or cover his costs of hosting.
I think that anyone going down the route of building a PC is going to do additional research and would be happy just to use posting as this as guidelines or starting points.
This looks cool, but I increasingly seldom I find myself watching physical media. I'd be more inclined to fore-go an optical drive and buy a case like this:
and just rip my physical media ahead of time. Although here in the U.S. I think it may be technically illegal to back up my DVD and Bluray collection onto a hard drive (thanks to the DMCA).
The author reused his last HTPC case. If you'd read the article, you'd know that he didn't put an optical drive in, he used the space for another hard drive.
Ah, missed that part. Personally I'd still like to have the aesthetics of a case without the 5.25" slot, though if I had a way to hide it away from view it wouldn't matter.
My setup probably isn't as energy efficient, but I am proud of the fact that I can control my 'dumb' TV with my phone: http://csmatt.com/notes/?p=32 (also contains comments on different media center applications available.) There's also this post http://csmatt.com/notes/?p=62 about hacking the LG Wireless Media Kit (AN-WL100W) to use the same HTPC to feed a TV in the bedroom.
Also of note is that while this will handle 1080p fine, it will struggle with a video renderer like madVR (depending on the settings), which can offer better video quality.