Wonderfalls is probably the best cancelled show that I can think of right now. But in a close second is Due South, which was cancelled three times before it finally stopped coming back from the dead like a New York City cockroach.

These horrible flops make great DVD box sets, though. You can buy close to 48 hours of Due South for less than the cost of one season of Friends, and you'll be awarded hours of Canadian Mountie hijinks. Who doesn't love wacky Canadian mounties stranded in Chicago in the 90s with a deaf wolf and a squirrely Italian?

Perhaps Canadian TV is just too cutting edge for the US market...but there has got to be a show you loved that only lasted for one season.