Windows – What are good linux programming environments for windows

Especially for Rails, I've found that development on Linux is generally a lot nicer than on Windows. However, I still prefer Windows as my main OS.

So far I've tried 2 options.

Dual-Booting with Ubuntu: The problem with this is I don't like having to reboot just to use Ubuntu, like if someone just asked me a quick question about a project.

Virtualizing Ubuntu with VirtualBox: This is pretty damn slow and freezes up at times, even if I'm doing basic stuff like text editing.

Basically, I'm looking for something that doesn't need to be full-featured, but where I can fetch repository packages that I need such as programming libraries. I was thinking maybe there's a Linux distro that's less demanding than Ubuntu that I can use, or some way to run a decent Linux within Windows without virtualizing. Any suggestions?