Motherboard / Raid for home media/fileserver

Hey folks!

I'm in the process of building a home fileserver, with a bunch of 1TB hd's and a raid controller or two. Primary purpose of this computer is to store media files, and personal files with some sort of redundancy!

What I'm thinking of doing is having three sets of HD's:
1. one 512GB HD for the OS/applications
2. two HD's for a raid 1 setup so that I can store personal files on there (photos, documents)
3. 4 HD's for a raid 5 setup for the media files
4. and buying a server tower with 10+ bays with the hopes that if I need to expand hard drive capacity, I would buy another raid controller and setup another raid 5

So, my questions are basically as follows;
1. Is that a viable setup, and/or is that a good setup?
(for example, maybe it's not possible to have the OS HD and the raid 1 HDs separate - and is in fact better to put them together?)
2. What kind of motherboard would you suggest for that? What kind of features should I expect?
3. What kind of raid controller should I get? I know next to nothing about the quality of raid controllers, and it would be nice to find out what are the things I should be looking for
4. I'm assuming to use the MOBO's raid controller and an additional HD raid controller right?
5. For potentially 7 HD's, how big of a powersupply (PS) will I need? How about 11?
6. Unrelated, but is it worth investing in the hard drive enclosures with a builtin 40mm fan, LED display (with temperature, and disk activity) and hot-swappable capability?
- I want to extend lifetime of these hard drives as much as possible... but also minimize the fan noise and power consumption.

Thanks!
James