It depends upon requirements you have. I have seen couple of host running VMWare on their servers for spam filtering and anything. If you hardware has capacity you can use VMWare as well as Webserver application. I would not suggest to use Database server with vmware that may cause problem.
Anyone try running VMWARE server on a production machine?
Run a couple of VMs underneath?
Is this safe / secure to do?
I have a friend who is testing out VMWare server, he likes it and is fine with the performance, but then again he's on top of the line hardware(6 SaS drives, 32gb ram, dual quad's, etc). As for security, I don't see why it's not secure, I've never heard of VMWare putting a product out there that isn't secure.