Well, after reading through all of this I'm going to throw out there that I'm going with capital gains (long term in my case) for 2013. The IRS is still "researching cryptocurrencies" so until they provide guidance I'm taking the 'report and be consistent' approach. For me personally the cap gains is essentially tax free because I had losses in a start-up I invested in, so it's going to net to below 0, and had I gone with the bitcoin-as-a-currency classification (income) I would owe a high tax rate and not capture the cap gains netting benefit. If the IRS doesn't like it they can provide guidance or re-calculate it for me I guess.

steverabincpa what do you think?