IMO, a language derives the most of its real-world utility from (good, updated, relevant) supporting libraries. This is a great reason to learn python AND ruby.
(Personally, I have a project where I'm debating the two. I've decided Ruby for now but may move to Python. I hope I never do PHP again.)
I realize that this does not have much to do with the topic of this thread, but I wanted to share a quick tip with you from the perspective of someone who spent a fair amount of time debating Python vs Ruby.
I love Ruby because it is really an amazing language (and I knew about and loved Ruby before Rails ever came into the picture). I also love Python - it was the first language that I ever finished a major project in, and it is an equally amazing language.
They are both similar enough to make favoring one over the other an extremely difficult decision. At the same time, the differences between the two languages are strong enough to make it so that you will miss the features of one language when you choose the other.
I literally spent weeks agonizing over which one to choose for a major project that I was about to begin. Finally, I realized that I would have to make a decision if I ever hoped to get anything done.
In order to make my decision, I simply made a list of the libraries/modules that would be helpful to me in completing my project. Then, for each item on this list, I looked at the status of the pre-made solutions that were available in each language. Where there was no library available in either language I just crossed it off (I'll write it myself).
When I was done, I looked at the list and choose the language that satisfied the most of my 3rd party library needs. For that project it was Python. When I repeated the process for a different project, then it was Ruby.
The important thing was that I was able to overcome paralysis by analysis and finally get some coding done. I don't know the size, scope, or nature of the project that you are working on, but I hope that my experience is able to help you in some way.
(Personally, I have a project where I'm debating the two. I've decided Ruby for now but may move to Python. I hope I never do PHP again.)