The taxation issue for Bitcoin is interesting. One thing I can say for sure is that it is NOT a currency. The definition from a taxation law standpoint is "virtual commodity". This is the case at least in Finland, I had to verify all of this from the Finnish financial supervisory authority because I'm starting a business that will sell bitcoins.

I have to add VAT (value added tax) to the price of bitcoins but to go around the problem of needing to add 23% on top of the whole amount (which would create a ridiculously high price for the coins), my business will actually do brokering for our customers so in principle we use the money deposited to us to broker bitcoins from an exchange to our customers and then we only have to include the VAT in the fee we take from the brokering.

Another note, I'm pretty sure that there are a lot of Bitcoin enterpreneurs who are either not paying taxes at all or are somehow doing it wrong. My business will do it by the book from the start, that will save me from the troubles to come when authorities start to get more interested in Bitcoin businesses.