If you don't need packages like Squid or Snort, you can also use the embedded NanoBSD versions which would suit the 8GB SSD quite well. You do look like you only need the pfsense box for basic NAT and firewall duties after all.
I hadn't realized they have SSDs in such small capacities. Time to get a review sample from them and crack it open then...
On the hardware, you might want to get 1 more stick of ram for dual channel (it's cheap anyway). Oh and the PT dual port is available in open-box form for just $129 ($50 off the OEM) as well.
The link is here: http://www.newegg.com/Product/Product.aspx?Item=N82E16833106014R
You can also consider the Zotac H55ITX-A-E (it comes with onboard Intel PCIe GBe, the C-E doesn't) with a G6950. It's faster and also very energy efficient. Not to mention, the board comes with a mini-PCIe slot and a wifi adapter (take it out and use it elsewhere or sell it off)