So why not look for a technical cofounder who is quite competent in either python or ruby. Then you can have them do the bulk of the coding and possibly oversee some development by other freelancer/s. Head to a ruby or python meetup, ask if you can jump up for 2 minutes and introduce yourself. There will probably be cofounder speed dating type events in your local area as well.
To pipe up about languages and frameworks, make sure when you build that you are considering Service Oriented Architecture (SOA) so when the time comes you are able to break off the pieces that experience higher load. http://en.wikipedia.org/wiki/Service-oriented_architecture
We're now heavily Backbone-based on the frontend, however. You should use what you're most comfortable with, as being able to iterate quickly is most important at the start of a project.
As mhd says, the backend is really more important. We're using MySQL, Redis, Cassandra, and a custom Erlang/mnesia based store in ours.
(full disclosure - I'm Stipple's co-founder and CTO)
There isn't really any reason to pick Django over RoR besides the fact that you know one technology better.
Although, personally I prefer Python because scaling Python via Cython plugins is far easier than RoR via FFI plugins, since you just take prewritten code and annotate types and algorithms to get to the bare metal.
You mentioned that you are an idea guy with a budget, why don't you get in touch my email is in my profile.
RoR-