I would come back about 2-3 weeks before your intended purchase date. Whatever we recommend today will probably not be the best bang for the buck in a few months. This industry moves too fast to try to plan a build 6 months in advance.
To give you an idea what's about in your price range look over these recommendations: $750 PC
You could "step down" in price on a couple of the parts to be able to fit a 22" LCD ($150), Vista ($100) and Keyboard/mouse/speakers ($50) into your budget.