As one member stated prior, bitcoin is more of an investment vehicle as of now. It will establish itself as a currency in the future.
I don't think it will be a currency, though. Despite its name, it's just not viable without changes to the underlying code. I think an altcoin will take over and be the true currency, with Bitcoin being for larger transfers or just remaining an investment vehicle. A currency relies on ease of use and speed. Bitcoin lacks the latter.