I spoke with a distributor for lithium motorsports batteries. He thinks they're a fantastic product, but he also thinks the training and dealer support to maintain these high tech batteries isn't widespread enough yet. If you forget to turn off the ignition and run down the battery, then you will need the smart charger to revive it.
He thinks they are more useful for race bikes that need to save weight. Maybe in a few years they will be much cheaper and much more common.
I like Vivo's bigger battery idea if you really want a new battery. A bigger battery that stays more full between charges will last longer. A thinner when cold synthetic oil like 5W40 is a good idea too, as it is easier for the engine to turn over and start lubrication.
But like the others have said, the current battery is sufficient unless there are signs it cannot turn the motor over reliably.