I tried the trick of punching a screw driver through it and loosening it, BUT if it doesn't work you end up tearing the lower part of the filter off and it can be a pain to the get the rest loose.
Matco makes a filter wrench that fits over the bottom of the filter. It might make things easier for you. As a couple of folks said, you should try it with the filter hot.
I don't know why some mechanics want to tighten these things so much. I have a coolant filter on my truck and tried to change it last month. I bent my filter wrench trying to loosen it. The filter is up near the top of the engine and is fairly easy to get to. It's insane that they felt the need to tighten it to 100 Ft Lbs.