CPU advice for NAS/HTPC/Media Server

I just bought a Lian-Li PC-Q25 Mini-ITX case and 4 1TB drives (2 WD, 2 Seagate). I want to use this to replace my existing NAS, and also for a media server (something like Plex) and HTPC.

My requirements are:
At least 5 SATA ports, at least 1 SATA III for a SSD system drive.
CPU able to handle transcoding (mostly down conversion to iPhone formats) and HTPC playback.
Integrated graphics.
Low power/heat, this will be on 24/7.
Cost is a factor (budget around $500 for remaining parts), but I can be flexible.
I can be patient and buy things piecemeal as they go on sale.
Also: the PC-Q25 limits PSU length to 140mm and CPU Cooler to 80mm height.

Here's my thoughts, I'd like to hear recommendations for what to change:

AsRock FM2A85X-ITX (7 SATA III ports)
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

AMD A4-5300
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Arctic Alpine 64 GT CPU cooler
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

FSP 400w MicroATX PSU with ATX bracket
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

8GB (2x4) Crucial Ballistix Tactical (low voltage, low profile)
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

...plus whatever 64 GB SSD is on sale.

I can't decide if the A4 has enough juice, or if I should step up to an A8. The other option would be an LGA 1155 board with a low power 35W i3 - though that may need a PCIe SATA card to get enough ports.