Do I still need apache httpd?
Web applications in an enterprise are not homogenous. I am sure that I am not alone when I state that there are many different development groups developing different types of applications and not all of them utilize the same web container. I am sure that I am not incorrect in stating that web application developers are capricious and don't necessarily think about the container in any way other than knowing the minimum necessary in order to deploy an application or any updates to the application and in many cases, don't even know what is providing the http support within the jsp/servlet container. Heck, we still get jdk installation requests for tomcat servers and the jdk hasn't been needed to compile jsp's in years. There are lots of different java application servers out there and there are lots of other types of frameworks out there that are completely java independent that somehow make their way into an enterprise. Every one in operations has experienced at least one instance where some guy in marketing with a budget contracted out a job to some boutique and the next thing you know, you're integrating some Rails or Turbogears app within your traditional java app serving infrastructure.
This is where apache really shines and nothing really compares. mod_perl, fastcgi, mod_jk, mod_proxy, etc. provide enough back-end connectivity options that you can front-end any kind of application server--including IIS with apache. Apache really is a robust universal gateway.