Let's look at some of the factors at play here:
1) The hacking is over with. Between Mt.Gox, Tradehill, Intersango, Cavirtex, and the other reputable exchanges, we've seen a reliable streak. Amateur night is done.
2) There are reliable ways to store your Bitcoins. With the exchanges mentioned above, e-wallets like Stongcoin, and secure wallets like Electrum and the Satoshi client, securing your investment is no longer a crapshoot. It's incredible to think how far we've come.
3) Publicity, publicity, publicity. In two days we've heard from Max Keiser, Fox, and Fred Wilson, and all in a positive light. Right there we've had three of the largest bouts of publicity for Bitcoin since its inception. What's coming in the next year? The sky's the limit, really.
4) Development. Mt.Gox is about to unleash a new round of products and services, one of them probably being their point-of-sale device, as was promised back in July. Tradehill is working bitcoin.com. Others promise easy ways to buy Bitcoins with credit cards; Crypto X Change is making it much easier, on a global level. FeedZeBirds is innovative. What's next? 2012 will be an amazing year for Bitcoin development.
5) Existing business is recognizing Bitcoin. Switch Poker was the first already-existing poker site to start accepting Bitcoin. Other online casinos have their eyes on Bitcoin and don't want to lose ground to the competition. Okpay started accepting Bitcoin deposits just recently. They'll soon be releasing Bitcoin merchant services and permitting Bitcoin withdrawals. Okpay is fairly large, with half-a-million accounts, but it's just a matter of time before even larger dominoes start to fall. These payment processors are seeing Bitcoin as another opportunity to make money, and like the casinos, they won't want to fall behind.
6) Global financial trouble. The Euro is done, kaput, over with, but it's not the only one. The Occupy movement is waking people up to the deceptive practices of banks. Financially-aware people will want to re-gain control of their money and diversify out of fiat currencies into alternatives like gold, silver, and Bitcoin. I already know a lot of people who invest in Bitcoin to hedge against holdings in their national currencies; more people will be doing it.
When you have a bubble like we've had, and then a crash, but then a definitive rise from the ashes, it's going to generate some serious publicity. Once investors realize that Bitcoin acutally ISN'T going away, they're going to pile on, and it will make the June 2011 bubble look like a speed-bump.