Someone told me once, that programmers tend to learn one scripting language properly and ignore or dislike other scripting languages. Do you have similar experiences?
 I'm using Python as my choice for scripting for  few years, however, I'm sure that there are many existing and emerging languages that could impress the Pythonistas. Can you recommend scripting languages that would be interesting and useful to learn besides of Python?
The only relatively unbiased answer you can really look for is probably statistical, and you would still have to account for the natural tendency of people to follow the path of least resistance once one is found or carved.
How many people learnt Python to a decent level, found the language resonates with the way they want to work, then move to something else because the language or the ecosystem, or both, don't support their needs?
I'd say probably a single digit percentage of the educated userbase, wouldn't be surprised if it amounted to less than 5%.
Unless you have work related prospects that involve a different language, or you need to move sideways for similar reasons, I'd say you're probably best off learning something complimentary to Python rather than similar or equivalent.
C++ for low-level or computationally intensive tasks, CUDA if your field can take advantage of it (med-viz, CGI etc.), whatever flavour of shell/sysadmin oriented scripting and hacks float where you work (bash, tcl, awk or whatever else) and so on.
Personally the reason I haven't bothered past a first glance with ruby, php, or a number of other languages is simply that it's better ROI to keep working on my python skills than picking up something that offers mostly the same qualities just in different forms.
If you really want to learn something else for the sake of opening your mind up a bit, and want to stick to "scripting", then LUA was an interesting toy for me for a while, mostly for the ridiculous performance you can squeeze out of a relatively easy integration process, and because it is a rather different set of tracks compared to Python. That, and the fact WoW plugins had to be written in LUA ;)
Learn a scripting language besides Python