Question to some of the storage pros Options

[Harkonnen]

I've decided to get this 4-bay drive enclosure or the cheaper non-raid variant.

The most cost-effective thing I can think of is to fill it with four 1.5TB WD Green power drives, running independently for a total of 6TB (5.5TB NTFS).

Or run it in RAID5 and fill it with four 1TB enterprise/raid-edition drives for extra speed and data protection. However, I've heard RAID5 isn't fool proof on rebuilds and having nearly 50% of the space seems like a huge tradeoff. (I'd need to get 1TB drives as I've heard the WD green drives don't work in RAID and I'm never buying Seagate again).

Thoughts? Any opinions would be great.

I don't really need speed so much as space and protection.

[Harkonnen]

Hmm, so if it's a software RAID, will it still work on things that aren't really PC's?
The way I understand it, my cpu cores will be doing all the parity calculation work.

I really want to hook it up to a Western Digital Media Player, which recognises all mass-storage devices.
Will this have trouble reading off a raid, or do you think the enclosure would do all the work for it?

EDIT: Oh yeah, I heard the green powers aren't good for RAID because their aggressive power-savings cause them to drop out of the array, and if two fall out it can result in catastrophic data loss. I do like giant unified volumes though.