I'm a beginner with Pylons and I've mostly developed on my localhost using the built-in web server. I think it's time to start deployment for my personal blog, I have a Debian Lenny server with apache2-mpm-prefork module and mod_wsgi - I've never really used mod_wsgi or fastcgi and I hear either of these are the way to go.
My questions:

Should I go with mod_wsgi or fastcgi and why?
Where should I be creating my web application? Should I create an entirely new user for it? Should I store it in /home/meder/web-app ? I currently have some php websites being hosted on my server and they live in /www/ which is a directory I created. Is there any sorta gotcha with static binary files such as images, as there is with django?
mod_wsgi.  It's more efficient.  FastCGI can be troublesome to setup, whereas I've never known anyone to have a problem using mod_wsgi with a supported version of Python (2.5, 2.6, 3.1 included).  WSGI exists for Python (by Python, &c.) and so it makes for a more "Pythonic" experience.  Prior to WSGI I used to serve small Pylons apps via paste behind mod_proxy (due to massive issues with fastcgi).
Anywhere is fine, any user is fine.  If you're worried about security, you may wish to add another user.  You could create a home folder in /www/ if you were so inclined :)  Static binary files, images, etc., should be served separately if you can, but Pylons had (actually, I believe still does have) a method of serving these (this should be the 'public' folder).  I would still use a separate mount as Apache is more efficient at serving these than passing them through Pylons.
Pylons deployment questions