Two things I thought wouldn't be a problem since I started with BTC are:
A technically savvy person at work basically comes to me asking to buy BTC in cash. He has been waiting near a week going through the whole transfer/deposit process. This guy actually wants to start messing with this software that works as a mobile (iphone/android) betting application for friendly bets between friends with micropayments in BTC. His original idea didn't work with USD for obvious reasons.
We then literally discussed the idea of a mobile cash-->BTC truck that would just tweet it's location around the city. Yes it is *THAT* difficult to get BTC currently where a solution like this actually seemed practical right now.
Most people just don't want to mail cash or go through the hassle of deposits. Paypal got over this adoption hurdle by providing an application that gave people money to an email address. Most people were willing to do the steps required to get money they already *HAD* from someone. Look at miners - they spend tons of time/money just to get the promise of future $$$.
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Second, I convinced some friends of mine to accept BTC as payment. It essentially came down to the money argument again. They are a small t-shirt company and spend close to $15k a year in "transaction fees" between paypal/authorize.net. After explaining BTC (no chargebacks, little/no transaction fees, etc) they were sold to try the experiment.
http://babbletees.com/blogs/news/3494702-babbletees-now-accepting-bitcoins. Within the first 24 hours they had two transactions, someone tweeted to Shopify (Babbletees E-Commerce provider) that they should start integrating BTC as a payment method for their customers, and in response Babbletees opened a ticket with Shopify for same. You can imagine the buzz around their office.
If this story could be repeated with even a small percentage of the online stores in existence - this crap about drugs, money laundering, terrorism, speculation, market crashes, etc.. would all go away.
In closing, these two problems *MUST* be solved (getting BTC to users, and getting rapid adoption by merchants). If approached properly, this will insure the success of BTC in the future.