I live in Champaign, Illinois. My apartment during the 2000-2001 school year at 107 E. Springfield (a CPM building) had wireless ethernet service from AdvanceNet. The service was abysmal-- it was rare to get a packet loss rate under 20%, and the ping time was extremely high (average of 1/2 second) and extremely variable.
If you use Linux, download Pinger, a tiny set of scripts to record the packet ping time at 2-minute intervals. I wrote pinger to try to help AdvanceNet fix our service (but, sadly, they never did).
I've been much happier with Insight@Home's cable modem service, which is available at my new house.
You're welcome to examine the following PostScript plots of packet loss rate (black bar, from 0% at bottom to 100% at top) and ping time (0ms at bottom to 1000ms at top, grey bars outline 10%/90% extrema, black line follows median) for our first few months with @Home: