<p>I haven't been around Java development for 8 years, but am starting to build a NetBeans Web Application. When I walk through the Web Application wizard, it asks for the server I'm going to be using. </p>

<p>What would be the best and simplest server for me to start using with NetBeans?</p>

Since the NetBeans IDE is a Sun product, I would assume that the Glassfish application server would be a natural fit.
That said, one of the pluses of developing a web application in Java is that the interface for working with the http is standardized (i.e. the Servlet specification), so that you can pick any servlet container you want: be it Glassfish, Tomcat, Jetty or Weblogic. Since it sounds to me that you're experimenting and you want to use something easy to administer, I might go with Glassfish. However, be open to revisit that decision when you need to actually deploy your web application in a production environment. Be sure to check out other options like Tomcat or Jetty.