How about getting it working first? Like a client that doesn't take a day or three to download the whole block chain. Isn't there a client coming that doesn't need to download the entire block chain?
The Android app satisfies that need for mobile users. Fully functional wallet is only about 30-40mb I think.
There is a huge amount of missing infrastructure, like merchant software etc etc etc.
Bit-pay.com is leading the charge on merchant software. They just finished an OpenCart plugin and are working on subsequent plugins over the coming weeks.
Also, badass open source POS system here:
http://www.youtube.com/watch?v=o84SfChQ-S8&feature=BFa&list=FLA5mKDEEJaTCScoGRe0IXZg&lf=mh_lolz