My vote goes for the gell cell, I use a 4.5Ah gell cell, its cheaper than 2 stick packs, charging is not really a problem at all cause if it goes flat while your out(which is only going to happen if your having a hard time breaking in an engine) you can boost it with your car battery, or 2 stick packs, or the cordlessdrill batt... etc etc. And the best thing off all is that with a proper charger(gell cell micro processesor controlled unit) you get no memory effect and it will last 10 years.

TM