A motherboard for my main system would be my first order of business. I keep hoping I can pick up a 7100 board somewhere for a good price. I need the nubus slots and the board will perfectly replace the Quadra. I would likely bump up the clock and install secondary cache ram. I wouldn't mind another 16 meg but the system seems to be doing fine with the 24 I have installed now.
I also keep thinking about ISDN. I would like to have a fast netlink. With the proper set up and router I could use my second system to cruise the net while I still should have enough bandwidth for a few users coming in on TCP at the same time. The problem with that still is the monthly fee that the ISP gets. Not the price of the line or the hardware.
