Realize this is an old thread, bit lots of incorrect info here.
Cooked rice, if cooled and stored in an air tight container in the fridge, will be perfectly edible for 4-6 days, maybe longer if you have a modern, efficient (read expensive) fridge. In the freezer it will keep until the end of time, pretty much, but may not be as tasty after 6 months or so.
If the rice smells bad when you open it, or is slimy or miscoloured, discard it.
If left out after cooking, or kept warm, discard after a couple of hours.
Don't be tempted to just store in a bowl covered with cling film, or uncovered - it will not be safe to reheat after a couple of hours.
Rice does contain protein, but not much, certainly not a high protein food as suggested above. Cooked rice is approximately 3% protein. The risk is due to a rice specific bacteria that can be incubated if kept warm or if reheated after storing incorrectly: the resulting food poisoning can be extremely serious.