Macs tend to be popular in the web development circles due to a few factors:

1. Out of the box to up and coding is very quick. Ruby as well as PHP and Python, are installed by default. The OS also has the Apache web server built in to test with locally.
2. Very easy to test in various browsers, including iOS using the XCode simulator, and Android via it's development environment. With a few Windows VMs, you can cover IE testing needs.
3. Unix OS under the hood with enough parallels to the Linux servers the code is likely to be deployed to. Or just run a Linux VM to get the full test setup locally.

I can't speak too much to the languages. I do know Ruby was the hot thing in 2011 for web developers, not sure if it's already shifting yet. Essentially though, if you want to get into web development, you need to also develop Linux/Unix skills. A Mac can also be a more gentle introduction into this world then a pure Linux machine, or trying to graft Cygwin and other bits into Windows.

If you do go the bootcamp route, please share the experience here. I'm curious to see how effective they really are. For you, it sounds like you have some of the basics already for programming, so mapping your past knowledge to the newer languages shouldn't be too painful.