Hi,
I think the stock batteries that come with the Macbook Pro are currently the best available, but there will probably be some better ones provided by third parties in the future as battery technology improves - there always are.
You can buy extra batteries from the Apple Store (although these are a bit pricey - I would check on eBay) and you could just carry one or more of these around, and swap them in and out as required.
I have noticed now that you can get airline adapters now to power the machine on aircraft, from the Apple Store, and I'm currently trying to buy an inverter to power mine in the car. When are you finding that it is running out of battery?