Thanks... the adapter (on the 9V setting) puts out about 9.2 V. This seems to stay constant with varying loads from the Arduino. I'm assuming that the Arduino board can easily handle a few 80mA fans.
One last question... does it really matter what kind of wire I use to connect the fans? I thought about using some spare Cat-5 Ethernet wire. Too thin? Is it better to use single-conductor (single-strand)?
I get paranoid about things I don't understand. Hence the need to understand them... 