are you going to plan on listening to the system with the engine off for a period of time, where you need deep cycling capability...or do you need a starter battery?
what if you want the best of both worlds? I'm thinkin about upgrading from my ac/delco stock battery replacement cause I do find myself listening with the engine off at times extending into the hours range (...and constantly checking battery voltage with the dmm). Plus on isolated incidents, my startups seem pretty weak like there's almost no power, which I'm guessing is the battery.
well, i've used a Yellow Top for a year now as a primary battery, and never had a problem starting it...but then again, I don't live in a really cold climate.
Batteries for deep cycling and starting are really two different designs - I guess the best would be to have one of each.