After about a month of usage, here are my initial findings on what you can expect in terms of battery life from your Pentax K100D Super digital SLR camera.
Using the set of Alkaline batteries included with the camera I was able to take approximately 90 shots with about 60-75% flash usage.
I also picked up two sets of 4 Energizer Lithium Ion single use batteries. I plan to keep these as the emergency set in my camera bag. I expect this set to perform close to, or exceed the anticipated number of shots in the manual. If I were to take a long trip, I would also consider picking up a set or two of CRV-3 Lithium batteries as these are supposed to yield 1000 – 1100 shots.