I used to go with "theme" name like wine oriented (chardonnay, merlot...) But after a while it gets confusing to remember which machine does what and switch to more "functional" names like "worker01, worker02, db01..."
If you're geeky enough about your theme, you could use theme-based names that are also functional. For example, all the wines are application servers, all the beers are DB servers, etc.
