I do NOT recommend NiCads. The danger of LiPos is often really over-stated. If you use a proper charger you are almost certainly fine. (In three years and countless charges on dozens and dozens of batteries, I've had zero problems.) For extra security, some people charge them in a 'LiPo box' or just a kitchen pot or other fireproof container.
If you really really want to avoid LiPos, look at LiFE (A123) batteries.