If you get something that uses 18650's, I recommend an "efest Luc V4" (or V6) charger. Comes with a wallwart and a car lighter adapter.
I recently used mine on a 600km trip and it charged my batteries at 1A each in no time. It'll do 2 batteries at 2A each if needed
It will also charge a phone at 1A via its USB port.
http://www.efestpower.com/index.php?ac=article&at=read&did=412
I'n not affiliated with them in any way, but this thing has lasted me ages (and the S2 I had before it still works, even after my Kelpie chewed it... It's my work charger)
EDIT: Just don't buy their batteries... I use LG HG2's