Deal: SanDisk Extreme HD Video 16GB SDHC 2-Pack w/ Case for $55 + free shipping
Beach Camera and BuyDig offers the SanDisk Extreme HD Video 16GB Class 10 Secure Digital Card 2-Pack, model no. SDSDRX3-016G-A21, bundled with a Zeikos Tri-fold Memory Card Wallet, model no. ZE-MC3A, for $55 with free shipping. That's $1.72/GB.
Don't forget, if you're purchasing from BeachCamera or BuyDig, make sure to use Mr. Rebates Cashback and get 1% cashback!
*UPDATE* 10/4/2011 - Of note, Adorama has a deal on the same cards but does not include the memory card wallet for $54.90.