I doubt you'll get much useful feedback because your question is too broad for a mailing list answer. If you're looking for basic performance guidelines, I recommend Greg Smith's "PostgreSQL 9.0 High Performance" [1] (disclaimer: I used to work with Greg and got a free copy), although I don't think he spent much time on running virtualized (which certainly could affect things). Then if you have *specific* hardware or query questions, this list is a great resource.
