The value of learning all those different languages is not that they're immediately and obviously useful. The value is that each one has a different set of tradeoffs and assumptions, and being fluent in all of them will teach you how to think more flexibly.

Sure, a beginner should use a language where he gets feedback and support. But a beginner who aspires to be a real programmer rather than a 9 to 5 coder will need a much broader base of experience than he can get by only working in one or two languages, and understanding that sooner rather than later is key.

I may have misinterpreted what he wanted, but if you're asking 'how do I learn to hack', it's a whole different question than 'how do I learn to write mediocre web applications'

If your goal is to learn to build rails sites, start with rails; however, if your goal is to be good at programming and subsequently be able to build things that other people can't, in the sense of PG's hacker advantage, then you should learn to hack, not build rails apps.