nik: 220 CCA's will get the job done. can't go wrong with yuasa, deka, or interstate. i would stay away from the $29 POS evilbay jobs. but in the world of frugalness i have to admit that we sell a ton of BS brand batteries and they last about 3 years in a buell, work well, fitment is perfect, are sealed after activation, and cheap.
you could go on the interweb to Battery Mart I order a battery from them it is called the big crack 220 cca for $ 75.00. they are in Virginia I am in Pa had it the next day,