The thing is that it should come up naturally in conversation, then the conversation should flow to the next thing. If someone just comes up to me and starts telling me about internet money (which, after watching that recent Bitcoin TV, is what I imagine Bruce Wagner does) I will assume its a scam they fell for. Also, if your goal is evangelizing rather than just passing along info, I would recommended quoting a value slightly below what it is now (or at least round down to the nearest dollar). It is also good to have other interesting things to talk about as well that establish yourself as a source of interesting information, bitcoin being only one example.
That is kind of rambling, but I really hope there aren't people out there just being like "check out these bitcoins they're awesome".
This. Usually, if I talk about Bitcoin (and I don't, that often) , it's just to start a discussion about related subjects - centralized planning, currencies, financial systems, the Internet, free markets... Bitcoin just happens to be an interesting example of a very different approach to a lot of these things. Generally, if the discussion includes an explanation of what the system is, and that it can be traded for other currencies or goods, people will ask what it's worth, and I can't really answer that without giving an outline of the rollercoaster ride of the exchange rate, and end up saying I bought some when it was cheap (relatively speaking), am theoretically well in the profit zone still but really wouldn't like to say where it's going to go next.