I replaced the battery in my 96 GSF600s in September of 06 with one from AutoZone priced at about $65. It crapped out on me 3 weeks ago. I always kept in on a float charger.
I replaced it with a Sears Diehard Gold with a 9-month warranty for $65.
I'm sold on Diehards for my cages, so I'm curious to see how it will perform in the bike.