<p>What to use for a medium to large python WSGI application, Apache + mod_wsgi or Nginx + mod_wsgi?<br /><br />
Which combination will need more memory and CPU time?<br />
Which one is faster?<br/>
Which is known for being more stable than the other?<br /><br />
I am also thinking to use CherryPy's WSGI server but I hear it's not very suitable for a very high-load application, what do you know about this?
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<strong><em>Note</strong>: I didn't use any Python Web Framework, I just wrote the whole thing from scratch.</em><br />
<strong><em>Note'</strong>: Other suggestions are also welcome.</em>
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One thing that CherryPy's webserver has going for it is that it's a pure python webserver (AFAIK), which may or may not make deployment easier for you.  Plus, I could see the benefits of using it if you're just using a server for WSGI and static content.
(shameless plug warning:  I wrote the WSGI code that I'm about to mention)
Kamaelia
will have WSGI support coming in the next release.  The cool thing is that you'll likely be able to either use the pre-made one or build your own using the existing HTTP and WSGI code.
(end shameless plug)
With that said, given the current options, I would personally probably go with CherryPy because it seems to be the simplest to configure and I can understand python code moreso than I can understand C code.
You may do best to try each of them out and see what the pros and cons of each one are for your specific application though.