I'm thinking about spending 6 months learning another programming language. I'm good at PHP, and nothing against it, but I think it'll limit me if I want to do a startup, in terms of hiring smart people.
So:
What language (Ruby, Python, ...) should I learn?
Requirements: it should be well webby (ie. have libraries for all the usual web stuff you want to do), and be exciting/easy to hire smart people for.
There is no smart people in what you think "webby" is.
Smart people tend to be the master of their domain: data mining, capacity planning, operations, specific business domains, embedded magicians, security experts (the real ones, not the fake ones), OS masters, programming language linguist.
Most people can write RoR, Django, CodeIgniter apps (or, known as the CRUD app). Very few people can do Business Analysis, Data Analytic, understand (and fix, improve, innovate) Healthcare, or bend Oracle as they wish so it worth for their bucks (surprisingly not a lot people can do this).
You can hire a $100k Ruby developer that know Ruby inside out, but what are you going to do with that knowledge except to build a company around Ruby language? (improve VM, sell enterprise supports, etc). I don't think you'd hire this fellow to write a crud app. That would be a non optimal business decision.
Node.js is the new hotness. Alpha-programmers will flock there for a while just like they did with RoR. So you're going to hire these programmers for 2-3 years, 4 max before they jump out. What are you going to do with Node.js other than to re-write pretty much almost everything that exist in another platforms already.
New language/platform becomes popular, people (early adopters) flock to it, then the notable ones (the next early adopters) flock to it as well, then the rest. I don't mean to disrespect the people who improve new platforms but most problems have been solved. All they do is to re-implement that in another language. MVC, ORM, Caching, Routes are still what they are in other platforms.