I'm using Odyssey PC925. Not the smallest, but has plenty of cranking capacity, handy for tuning & track work, where you have to perform a few starts in a row. This has replaced an older PC800 that had an abused life, lasted 5 years.
A few guys with Lexus engines have been using smaller Odyssey batteries, no sure what sort of life they are getting out of them.
Also using a proper auto-charger, plug it in and forget about it. I reckon this is the secret to long battery life.
http://www.dse.com.au/cgi-bin/dse.st...uct/View/M9826