I run in deeply technical IT process and security circles so I heard about it early and I've been involved since Dec 2010, back when it made sense to run your own miners. At one point I had 3 pc's with two cards each running 24x7. The difficulty was so low back then that you'd hit coins all the time, and of course they were worth less than the electricity required to find them. There were guys then (and now) running basically their own small data centers full of miners, and a bunch of guys in the bitcoin world that would sell you mining capacity without people ever having to buy their own hardware. I'm sure all of that is still around.
I sold off a bunch on mtgox, right around the time of the 1st breach, during the 1st run up in 2011 and made some crazy money on it. Sold more just a few weeks ago, and still have a bunch left over. I'm being purposefully obscure about the exact numbers here.
At some point in late summer 2011 when the difficulty increased I switched over to a mining pool, BTCGuild I think, and did that for a while, until eventually stopping and selling off my hardware. This was another area where for a while you could have bought specific GPU's and sold them for way above market price. Not sure now though...haven't checked those prices in a while.
As far as my opinion of it, it is what it is. I don't see it really ever being a form of currency that will have any impact on LEGO sales, mainly because the privacy aspect of Bitcoin is really irrelevant. IMO the privacy aspect is really the only reason Bitcoin has the value that it does. Also, the value of Bitcoin is too volatile for LEGO sales.
At this point I can't see someone just getting into Bitcoin...that ship has sailed unless there's a total crash in the market then you might want to buy some up. Or, I could be wrong and in a year they could be worth 10x what they're worth now.
I also have many Namecoins as well, which is a Bitcoin derivative.