As i mentioned "if i am not wrong" which means i am doing this on my own assumption and experimentation.
I bought a lot of SANYO Ni-Mh 2500 batteries before and used the "safer" slow charge but ended up most of the batteries didnt last. Of course the batch could have been defective for one.
I am using a MAHA charger which can determine charge required and shut off auto. I also referenced studies which can be found in GOOGLE.
Here is one
http://www.maxim-ic.com/appnotes.cfm/appnote_number/3501
These Powerex 2700mAh NiMH AA are trully superb. On an average working day i shoot about 100 pictures and i only need to recharge the batteries once a week and i only recharge them when they are about 50% charge left. I use a battery checker for this. This way i only recharge them when they need to be. I think this extends the life too.