[lincpimp]

Generally you will need an esc with a low voltage cutoff, or run an external lvc that will pulse the throttle channel when the pack voltage drops.

The Castle esc like the MM and sidewinder are great choices as they have built in lvc and can run brushed or brushless and they are cheap.

Another lipo benifit is the very strong voltage holdout, they do not drop off like a nimh battery will. Honestly nimhs suck and should be retired to the old technology wing and left to gather dust...