Thank you. That's exactly the kind of criticism I'm looking for. Bottom line is bang-for-the-buck. If a couple of beefy individual systems will get us what we need for LESS than the other setup would require, then I'm all for that.
(Oh, and you've probably done it by now but if you haven't, for pity's sake secure your router or you'll be sharing your broadband with the world. ;-) )
Found that advice on FR a couple of years ago. Made all the suggested changes and then some to secure the router, so I reckon we're safe enough from amateurs.
About bang for the buck, you can easily put together some new, cheap systems for under $350 each with Linux. As long as your main hard drive in the system you designate as your server holds enough, you will be absolutely fine on speed as well as assuring Linux programs will work well and display on each system okay.