Hardware configuration is really site dependent, and should be done as part of the upgrade planning with Mincom resources familiar with your database size, concurrent users, etc.
You can have the database and the app server running on different machines, but I don't see much benefit in it unless you already are doing this with other applications and want to centralize all your databases in once place. It is much more common to see one machine running production, and another running development and test.
Whatever you do, I recommend running Webview on a separate machine from the Ellipse server.
Best bet is to have your Mincom account rep arrange some time with a technical consultant that can discuss this in more detail after reviewing your site information.