You were probably expecting somewhat biased feedback given that this
is a Ruby list, so here it is: Ruby makes me smile.
But I can be more helpful and nuanced than that:
It depends on where you're coming from. If you've only enountered
business-y web-y Java or C#, then Ruby will be a breath of fresh air
and (especially in the Java case) will expose you to "new" ideas that
will help you move your programming skills forward. Once you "get" it,
you will find yourself much more happy and productive than before.
On the other hand, if your thing is writing code that is as fast as
possible using as few bytes of memory as possible, you will want to
look elsewhere. Bear in mind though that there are many many problems
out there for which developer productivity is more important than
saving a few bytes here and there.
Also be aware that you won't ever be able to hit pause on learning.
Even for the web where Ruby is most popular, you would need to learn
some (actually, a lot of) Javascript in order to give the kids the
kind of experience that they have become used to with Facebook. Then
if you get to a stage where performance actually is important, you
will want to be able to handle bits and bytes in C, or (probably more
likely these days) find something that lends itself to multi/parallel
processing.
Tell us more about what you've tried already and or what you want to
do and we can give you more helpful feedback.