Just out of curiosity (and some Friday fun), what do you use for powering your receivers/servos?
I'll go first:
Foamies and balsa up to 51" wingspan: ESC built-in BEC. Typically ZTW or Castle
58" Edge: 10A Castle Creations BEC
Beast 60e (58" wing span biplane with quadruple aileron servos): 2x redundant 2s 1800mAh LiPo through powersafe.
71" Slick: 20A Castle Creations BEC
72" Extra (gasser): 2x redundant 2s 2300mAh LiFe through batteryshare.
76" Edge: Single 2s 2200mAh LiPo (will upgrade to redundant "one of these days...")
88" Slick (gasser): 2x redundant 2s 2200mAh LiPo.