Don't waste money on expensive battery. If you can only have 1 battery, just get one that fits. Most AGM batteries can deep cycle a bit so the Deka Intimidator would be a good choice without spending crazy $$. If your current battery is good, just keep using that.
If this is for a second battery, then a Marine/Deep Cycle works pretty well. If you stay with a normal lead acid battery, you'll be out the door under $150. Costco has an Interstate Marine/Deep Cycle that holds up well and is under $100.
Here on expo many people equate more expensive with better, and certainly in batteries, that isn't the case.