Get yourself some high-capacity Ni-Mh rechargeables and a decent fast charger, and remember to charge the batteries before you want to use the camera. Ni-Cds hold their charge for longer, but are lower capacity. Regardless of which ones you use, make sure you usually remove the batteries from the camera when not in use as the Canons recharge their internal battery when the power's off, so the main batteries will drain (keep them in every now and then so the internal doesn't go dead).
