I think Ripple is very interesting, but I am not convinced that the "trust chain" works well enough for arbitrary situations. I just want to buy something from some random online shop without needing to figure out a trust path to them.
The Ripple system would do that for you as long as it has a well connected user base. As its biggest problem, the Ripple Project has yet to develop a decentralized model. A Ripplypay user can't send an IOU to a Rain Droplet one. I think the Ripple Project might benefit from integrating with or borrowing ideas from the Diaspora project.