Funny, battery brand is one thing I've never been that choosy on; what I've always done is buy the recommended group & size, and if there happens to be a slightly more powerful one available (better reserve or higher CCA) that fits then I'll buy that.
I just accept that I'm going to buy a battery every few years so I don't get too caught up in it.
Others swear by Sears, Optima, etc. and will probably weigh in with their experiences and reasons for choosing what they choose.
If I were in your shoes, I'd simply hit the closest AutoZone, NAPA, or similar, buy the best they have that fits, and be done with it.