Death to Squirrels

Our street is plagued with vicious mutant black squirrels that no one else is subjected to. They chomp off the tops of tulips, they dig up new seedlings, they take bites out of eggplants then throw them on the ground as though deciding they don't like them... yet they then try another one. Two summers ago they were even ripping through window screens in our house and three other neighbours to break inside. One day a squirrel stole a bag of fresh market bagels off our kitchen table. I'm not joking.
It's really alarming how much devastation they cause and there seems to be no cure. Yet I see beautiful tulips on other streets, I talk to other gardeners about it and they express shock at our problems. Even the other side of the street seems safer.
My neighbour to north side is in complete sympathy. He shoots them with a Super Soaker and shakes his fists at them. It's a good stress relief but is not very effective in keeping them away. The biggest problem is that there are no predators in the city to keep their numbers in check.
We tried building a chicken-wire cage around the plants that they like the most, which was somewhat effective; however, the cage didn't get enough sunlight so the plants didn't do too well. I would happily applaud a city plan to cull the little buggers.
When I express my blood-lust to gentle hearted friends they say "have you tried cayenne pepper." Ha! The squirrels seems to like my garden spicy, maybe they are Mexican. Is there any more effective method that won't hurt the neighbourhood cats? I just want to spend one growing season where I'm not constantly trying to out-wit squirrels. I don't think it's possible. You've got to respect their intelligence. Loath them, but respect them.