Simply: what services and infrastructure do we need to have to enable greater pure Bitcoin commerce? I get the usual like groceries and stuff but what else?
Trust.
Without trust in merchants and customers, there will be no growth in the economy or usage of bitcoins. Any one product or service is irrelevant at this point. If I can't trust the other party in a transaction, I'm not going to do the transaction. Figuring out a reputation system/score by some identifier could go a long way towards building trust in trustworthy individuals and services. Here's a TED Talk as an overview of the issue,
http://www.ted.com/talks/rachel_botsman_the_currency_of_the_new_economy_is_trust.html . There is a bunch of research into this area as well,
https://duckduckgo.com/?q=journal+of+reputation+and+trust+research. Ebay, paypal, amazon, and others have had to figure this out. We will too.