I learned Ruby in 2007, and I’m very glad I did. Of the 6 or so programming languages that I’ve used for large projects, Ruby is by far the most powerful and best designed.
I learned Ruby (from the Pickaxe Book) more or less in the course of learning Rails, though I’d probably recommend that others not do this: it’s best to get a grip on the language itself before learning a complex framework on top of it.
And of course, the Ruby community is very much into proper development practice—testing, refactoring, modeling stuff correctly, that sort of thing. Learn from them!