I say HTML5. App Stores are great but they will change dramatically over time to direct delivery from the developers. Developers themselves will use HTML5 so they can break the dependence on App Stores and the distribution fees associated with them.
When Apple originally released the iPhone all applications were supposed to be network based. There was a big hue and cry until Apple relented and allowed developers to develop directly for the phone.
With the evolution of technology it is time to go back to the original direction of the iPhone. The real benefit will be that they will not have to develop for any specific phone and can support any and all of them with one application.
That is the real goal of any developer.