most widely used python web app deployment style
100 req/s is not that hard to achieve these days.
Consider the deployment that your framework recommends. Zope for instance, has a decent webserver built in, so mod_proxy_http is good deployment.
Since wsgi came to fruition, it has become the preferred mechanism for many frameworks, and they now the builtin web servers are only suitable for development.
Regardless of what you deploy with now, it's important to be able to switch/add parts of the stack as necessary - do you want a reverse proxy for static content in there somwhere? You may not need one if you use nginx as it can serve static content from memcached quite well.
Summary: use wsgi
I wonder which option is more stable (leaving performance aside) and is more widely used (I assume the widely used one is the most stable):

apache -> mod_wsgi 
apache -> mod_fcgid
apache -> mod_proxy_ajp 
apache -> mod_proxy_http

for a project that will serve REST services with small json formatted input and output messages and web pages, up to 100 req/s. Please comment on apache if you think nginx etc. is more suitable.
Thanks.