If you get a "normal" battery, and you dont drive it everyday the battery will die on you again and then you'll have to charge it back up.
Century batteries are good and reliable provided that they get a charge every 2 days. the part number is: NS40ZLSX or NS40ZLS (from memory) but these are very small batteries.. normally used in Jazz's, Civics and Corollas. Prices range from 115-135. One comes with a 2 year warranty one comes with a 3 year. You might want to invest in something bigger like a 57 or a NS60LS .. abit dearer but more Cold Cranking Power.
the prices i quoted you are from autobarn, im sure you can get it cheaper somewhere else.