One point to consider in all this is that SBS 2000 comes with ISA. In my last firm, where we had SBS, we bought and installed SBS 2000 during my last week there, so I am not as familiar with it, but I understand that it's a definite improvement over proxy 2 and IIS (it actually handles both functions). Back to Dave R. original question, however, I would be most inclined to buy or build a second box to act as a file server, offloading that function from the SBS. For now, I would either have the ISP change their MX record, to send their mail directly to them, or load the POP3 connector (I favor the MX change, but they can achieve tehir goals either way), and I would start budgetting for an upgrade to SBS 2000, or SBS.net, at some future date.