Which language or framework to pick for new startup?

Which technology stack has the best combination of speed of development, engineering costs and ability to easily find an engineer?

Both my co-founder and I are non technical and before we set out to hire someone on ODesk to build our MVP out, we would love to hear some first hand experiences.

There's PHP, Ruby on Rails, Django, and others. Any technical entrepreneurs would like to chime in and offer their pros and cons of which stack to pick?

Update:

We've narrowed it down to between PHP and Rails. After browsing ODesk and other job sites, it seems those two are the prevalent ones. There are very few developers with Django skill set.

Two things to consider:

1) If you're using the MVP purely as a proof-of-concept / platform for testing hypotheses, and plan on recruiting technical talent later, which development stack you build on isn't a priority. You should instead be choosing the contractor / contracting team based on their experience in building apps like yours and the number of positive reviews of their services. When you bring on a lead developer, data migration from the old stack to a new one if needed should be something worth spending the time on.

2) If you're going to be locked into the stack for longer-term (e.g. because you're building the MVP for a pilot customer who'll you'll need to support without a gap in development later), choose based on what's going to be easier to recruit for in your area. LAMP stack is pretty universal. MEAN is not.