Larry,
I was going to recommend the Labjack U12 with the NLSA Piggyback card.
https://secure.heze.lunarpages.com/~nlsa002/labjack/labjack_piggyback.html
It is/was a cheap way to get 12-bit precision, and plug and play with several tracking programs. It runs off a USB port, and I have an old USB 1.1 powered hub which powers it, and a couple of other components. This gives me a small amount of isolation from electrical damage to the computer. NLSA however reports that they are out of the Piggyback card, and are not expecting any more. The original package was so cheap that you couldn't justify building your own. However, it could probably be duplicated easily, depending on your skills. It uses a ULN2003A driver chip.
That having been said, if mine were to be vaporized by lightning, I would go with the LBV-Tracker, as I like its ability to use a USB port for control. The ARS Win is also an excellent program.
Alan WA4SCA