Battery chargers

I'm sure this one has come up a bunch of times.....

I got some NiCad and NiMH battery powered toys over christmas. Now the
NiMH is propriatary, so there's not much I can do about that. But the
NiCad ones are just 3 AAs bundled together.

So.... I need to get a charger for these. What I'm looking for is a good
quality charger that won't overcharge, in other words, something more than
the AC transformer, a diode, a capacitor, and a couple of resistors.
(That's what the factory-provided charger consists of.)

Ideally, I'd like to have a charger that runs off car power (12-14VDC) and
where the batteries can be stored (or forgotten) in the charger. I know
that's not ideal, but this is for a mobile use, and it's likely that these
batteries won't get the personal attention that the cheap chargers
require.

So, to recap, a charger that charges batteries, then, when full, shuts off
and won't drain the batteries.

I've fished around the web, but all I find are grandiose claims like
http://www.thomas-distributing.com/maha-mh-c204f.htm; I'm never certain
what I'm buying. Any reputable charger manufacturers out there? Any
places that specialize in chargers?

Thanks,

-Kamus