Maybe it's just me being paranoid but I usually wouldn't skimp on the batteries. IF the battery fails midflight, that's it. There is no dead-sticking.

I've used Radicalrc.com and their sanyo packs have done really well in my car RX so I know it's good stuff. Japanese quality cells and USA made packs... (not that I have anything against chinese packs, I just can't get myself to put a $400 plane on a $10 battery when I can get a proven pack for $10 more). Just my opinion of course.