Hi Mark,
I am working (and Arduino-ing) right now, I tried to find Portmon, on my laptop but so far no luck.
Plugged into the laptop is a wireless mouse, a HP printer (sometimes) and a wireless internet connection stick (I live in the country and that is the best / fastest / most affordable option), thats it, no USB hubs or anything. The Uno goes straight into the laptop usb port.
Bear in mind that I plugged it into the other computers, the one with XP did nothing (there is nothing at all on the USB system, even the keyboard and mouse are the old school plugs, and the computer has been reformatted and is basically as it was when it was new, there isn't even an internet connection to it. I put the unzipped Arduino 0022 into it from a flash stick via the USB port) and the other windows 7 laptop did nothing either when it was plugged in there either.
I will try and figure out which driver was installed, I pointed it to the drivers folder and it selected what it wanted to use, then worked once, then stopped, and now I cannot pull up the device on the computer to check on drivers................
As this is my first entry into dealing with the "non mainstream" parts of the computer I have a lot of catching up to do to get close to most of the other guys on here, so please be patient! Everyone has to start somewhere, I am fairly technically minded, so hopefully will start to catch on fairly quickly, we'll see.