my room mate has
this one I really like it because it has a display to tell you the battery voltage, % of charge and is a switching power suply so it is really light and efficent,
I have a pile of my own battery chargers and
use one like this for charging my electric car's auxiliary battery, I also have a charger that I can't remember the name of, but it has a pulsating mode to desulphate batteries, they are a bit harder to find but it will bring batteries that I thought were gone back to life.