Any suggestions on what to do while in town?[/QUOTE]
London is basically a college town (which is where I went to school - The University of Western Ontario), ala Ann Arbor, Madison, etc. Not much going on off campus, except in a small stretch downtown on Richmond Street. If you enjoy sports, UWO has good teams in most sports and the local minor league hockey team, the London Knights, were the Canadian champions last year. Not much of an arts scene that I remember, or fine cuisine either, but then again, I was only a college student back then. I was just back there this summer, and was amazed at how cheap things still are (food, drinks, hotels etc.)
The winter can be very cold, windy and snowy. Which brings me to my other point - definitely fly into YXU if you can (and I would do this via DTW, avoiding the customs/immigration hassle at YYZ). The drive to London (from either Detroit or Toronto) can be brutual during winter. I've seen many multiple car accidents along the 401. The last thing I would want to be doing is a 1.5 drive thru white-out conditions (which happens alot along the 401). Also, YXU is a small, quiet airport, easy to get to from the city centre, and the customs/immigration lines will be non-existent. The lines in YYZ can get long and crazy.
Hope you enjoy your time in London - I have very many fond memories . . .