Upgrading HTPC

[knight_40k]

Current Specs

Case: Silverstone Grandia GD08

Mobo: MSI 890GXM-G65

CPU: AMD Phenom II X2 560 Black Edition

Cooler: Zalman CNPS8000A

RAM: Kingston 8GB DDR3 1333 (2x4GB)

GPU: PowerColor Radeon HD 5450 512MB GDDR3

SSD: Crucial M4 128GB SATA3

HDD: (x1) Western Digital Caviar Green 1TB 5400 SATA2

HDD: (x2) Western Digital Caviar Green 2TB 5400 SATA2

HDD: (x1) Western Digital Caviar Green 3TB 5400 SATA3

PSU: Seasonic X-460FL FANLESS

OS: Windows 7 Pro 64-Bit

Other Accessories: Silverstone EC03B USB 3.0 PCI-E Card

I am thinking about upgrading but not because of performance, I just need more hardware expansion. I am using all SATA ports and storage fills up quite quickly. This system is used solely for video playback at 720/1080p via XBMC, nothing else whatsoever.

My mobo only has 5 SATA ports and I want more, either internal or by use of these or something similar...

http://ncix.com/products/?sku=70954&...e%20Technology

I haven't picked a new mobo yet so I'm open to suggestions but as far as CPU goes I'm thinking sandy or ivy i3 (or maybe AMD equivalent). I want my mobo to have native USB 3.0 support so I no longer need that PCI card and can use those slots for SATA cards (as linked above). I don't plan on using any RAID, I already have my data backed up, I just want to maximize storage capacity.

I am also thinking about replacing all of my 1-2TB HDD's with 3TBs and thinking about using Reds. How would they work as solo drives in non-raid config? or should I stick with Green? Note silence is key so Blacks are out. I'm also open to Seagate.