service like paypal and alipay.com
The bitcoin is very like cash, but when we do online business, we need the fund transfer very fast, I mean, done the transfer within 1 second. And paste the address every time is inconvenient, and keep the wallet.dat on the local computer just like you keep $1000,000 cash in your bedroom, which makes most of the people feel unsafe.
and for the merchants doing business with bitcoin, it's very fine to the super small one, as they only make one or two deal per day or even per week. but for those not so small merchants, like doing business tens of times per day, we need a more sophisticated payment service to overcome some problems.
If the bitcoin community have a wide accepted and really trustworthy service like paypal, the currency will be adopted by very large group.
one suggestion: go out and find some angle investment or venture capital, find some genius program and product manager you've got know in your life, and make it a serious enterprise!