Dell Dimension E520 Dual Core with Vista and Office @ Dell Outlet.
They are basically the same machine - but one comes with Vista Small business and Office small business and a 250 gig drive - the other is home and student office and vista home premium.
They are both a pretty good spec and a reasonable price. For the non small business one you'd be saving about $200 through the outlet but on the small business one its probably around $100 off the same machine (unless you use the code we have here - in which case your probably best off getting the new machine off the main site.
The best value is for people who already have a monitor (they dont come with one). The price I've shown here is for the non small business one.