One of the projects I'm working on is looking like we're going to need to migrate from CentOS 5.4 over to something else (we need to run Postgresql 8.3+, and CentOS/RHEL only support 8.1), and one of the options will be Windows Server.

Since 2008 R2 is out that's what I'm looking at. I'll need to run Postgres and Tomcat and don't really require anything that Windows has like IIS (if I can run Server Core, even better!). The other kicker is it will be virtualized through VMWare ESXI 4.0 so that we have three separate boxes: development, Quality, and Production servers.

From a licensing standpoint though, and I good enough with just the Web Server edition? Am I right in assuming that will be three licenses? Or should I just jump up to Enterprise so that I get 4 VM licenses?