No. It isn't worth the bother unless you live in the tropics. Rice is worthless, it absorbs moisture but can contribute it's own fungal problems. Silica gel packets will only absorb moisture until they are saturated, they then have to be reactivated in your oven. Putting a saturated SG packet in a camera bag can actually increase the humidity in the bag.
Originally Posted by ToddB
A camera bag is permeable, or at least not sealed well enough for an average size packet to actually dry it significantly. Keep the gear in a cool dry place, dry it if it gets damp before you put it back in the bag or case, and you shouldn't have any worries.