I really like silica gel. It's cheap and strong and can be regenerated at 250F.
I don't think rice is a very strong desiccant ... probably better when it is very dry. Someone posted the idea of baking the rice at a low temperature to get it as dry as possible before using it ... but never get it hot enough to turn brown, even lightly. The person posting the idea thought that would break down the rice's ability to attract humidity.
These are my articles on seed drying:
http://garden.org/ideas/view/R...
http://garden.org/ideas/view/R...
http://garden.org/ideas/view/R...
http://garden.org/ideas/view/R...
Paper envelopes are more convenient for seed drying than paper plates.
They can also be used for seed storage in dry climates.
I need some photos before this blog post is ready to be an article, but I have some suggestions for desiccants other than silica gel.
http://garden.org/blogs/view/R...
The idea of using "Oil Dry" (oil-absorbent Bentonite clay containing montmorillonite) came from Dave, but I haven't tried that yet, myself.