Oil Filter problems

Ok, just changed the oil on my 03 kat at about 850, I know the book says 600 but that was the only time I had to get it done. I changed the oil alright, but I had a problem with the oil filter... I couldn't get the dang thing off. Spent about 15 minutes by hand, and then went to autozone and picked up a special tool for taking off oil filters and other non sprocket type items. After 45 minutes, I still didn't have any luck. I ended up just putting the new oil in without changing the oil filter. My guess was that they just wanted me to buy another filter, which I did, soon after I bought the bike and that the original one can last to the winter, when I plan on changing it out.... My question is, does anyone have an idea how to get the oil filter off next time. I've heard driving a screwdriver through the filter with a hammer would work, but I'm looking for some other alternatives.

thanks