Alpha batteries look a good option, with free next day delivery and very reasonable prices on leisure battery's.
This is my current battery of choice, only because it was free, but i can charge cells and lipo's for 3 cars every sunday, run my laptop every sunday off a 1000w converter and only charge it once every 4-6 weeks.
http://www.cdstandbypower.com/produc...pdf/12_370.pdf
don't know what any of the numbers mean but my god it's F**KING heavy.