What would be the best way to set up my network with a central storage solution accessible(read & write access) by both Macs & PC's?

My setup is this:
4TB's worth of hard drives in USB enclosures (2 are USB 3.0, rest are regular)
2 Macbooks (1 with a Windows 7 partition)
1 iPad
2 iPods
2 Zunes
2 Android phones
Digital Camera's with an Eye-Fi card.

Ideally, i'd like ALL media stored centrally on the network attached storage and accessible by all devices.
-When I take photo's with my camera, I want the Eye-Fi card to transmit them to the central storage.
-When I download music from Zune Marketplace, I want them stored and saved to central storage.
-Wife uses iTunes, I want her music mixed in with the same music folder I use for my Zune downloads, and for any other music I download.
-I want ALL music & other media in a central folder location accessible by all devices.

Is this possible?
So far, I've got this router coming and hopefully it'll be a good base: http://www.wdc.com/en/products/products.aspx?id=740

My idea was to daisy chain all my external HD's to this router's USB port. That in addition the 1TB on board should be PLENTY of space for everything.

Now the only issue is backup.

I'm thinking I should just stick to 1TB increments for my externals....that way, I could have 1TB for media, and back up that drive to one of the 1TB externals. I can ditch the smaller externals I have and use them for something else or give them to family....

Does this post make any sense? Sorry for rambling....