I'm just starting to design my near future HTPC and I am at a crossroads here. Here is my current situation/dilemma:
My HTPC will be used most of the time for playing movies off the drives, a little playing dvds and bluerays, possibly for playing music, possibly play TV. I will be reusing my current microATX board that has 5 SATA ports, so I would have room for 4 HDDs. I was looking at a case that has room for 6 3.5 drives and I was planning on putting in 3 1TB WD Black drives. I have since changed my mind to an Antec Fusion which only has room for 2 drives. Therefore, I want to max out the amount of storage.
So, I'm looking at putting in 2 1.5TB or 2TB drives, but the 7200 drives seem a bit expensive. The 5400 drives seem much more cost friendly and will run quiet and not use as much energy. This seems like it would be a good option for an HTPC.
Will 5400 drives be adequate for playing movies, both HD and SD in mkv and avi format? Or will I need the faster spinning drives? I do not want loud, grinding drives, which I have with my 500GB seagate. I'm not sure if that is a problem with all of their lines, but I definitely want a quiet high capacity drive, and it must be able to play movies.
I am also playing with the idea of installing a 32GB SSD to run the OS and programs.
Go with the green drives. The transfer rates needed for recording or playing back movies are pretty trivial compared to even a slow green drive, and its low noise is important in an HTPC.
The only caveat would be if you will be doing more than a couple of things at once - for example if you have dual tuners and plan on recording two streams while playing back a third one - then the access time of the green drives could potentially become an issue if you don't have enough RAM for buffering and if the software doesn't use the RAM cleverly enough.
The SSD will be good for quick bootup times, which is probably also a good thing for an HTPC unless you plan to leave it on all the time.
I have build a few setups as the one you are going for, and can say that using WD Caviar Green have made for a great match, low power consumption, low noise when under use and plenty fast for full HD content.
But, what capacity? Some people say 2TB drives are risky because of the extra platters (more heads, more moving parts) so there's more of a chance of something going wrong.
Also, the new Advanced Format WD Green drives are a huge question mark. I've been debating between Samsung and WD Green (*my top two choices) for a storage drive and still can't decide. I'm mostly leaning towards Samsung F2 or F3 5400RPM models because of the uncertainty regarding WD xxEARS Advanced Format models. I use Linux as well as Windows and to align the xxEARS drives in Linux is especially complicated right now and requires extra preparation with no writeups. One has to go by various claims by people with different workarounds and alleged solutions.