Purolator PureOne. You can buy it at most discount auto parts stores. It's cheap, and actually one of the better filters you can buy. I can't remember which part # but if you do a search for Purolator it will come up. It's like PL14610 or something like that. Can't beat it for $6.
Here's a link to oil filter stuff from one of the other posts...credit to EZride for posting it.
I personally like the Purolator because it's blue and matches my bike, or the K&N for the handy dandy nut on the end. Don't forget a crush washer to the drain bolt (I always do)
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Beer is proof that God loves us and wants us to be happy. -Benjamin Franklin
Uh oh, someone's opening that can of worms again. Oil and oil filters have been discussed many times. I personally use the K&N as it is easy to install. If you want more info just do a search for "Oil Filter" using the nifty search feature below :-D