If it weren't for Apple's pricing restrictions, I would love to see a free version of Instapaper that is "unlocked" to a full-featured version if the linked account is a paid subscriber. (For those that don't know, Instapaper also utilizes a subscription model: http://www.instapaper.com/subscription)

I happily pay the quarterly subscription fee and would love a full-featured application to go along with it. That said, I no longer own an iOS device.