When Monero can have some use for private transaction, so that its usefulness is proven, then it will fly. Before that, it is all speculation.
I think the most compelling case at the moment, which will get many bitcoiners interested is a mixing service based on Monero, which will automate all the hassle of doing it through exchanges. I imagine an instant two way exchange service, which does not require login. Coupled with a small app, which sends bitcoins to the service, receive Monero, send to another Monero account, send Monero back to the service, and get back clean bitcoins.
Almost every day there is a question about safe mixing on r/bitcoin, and the only real way seem to be through Monero.
The developers of Anoncoin have hinted that they would try to build a trustless exchange once their current project is over.