Does fluoride in drinking water have any other effect on your teeth besides preventing tooth decay?

Yes. Fluoride is wonderful deterrent for dental decay when used appropriately however when taken in excess it can cause discoloration and malformation. This condition is technically called fluorosis. Contact your local dentist to find out the appropriate amount you should be taking.
No. The Fluoride that is added to municipal water is a very low concentration of 0.7 parts per million. That is well below the level of any Fluoride toxicity. Fluoride is a naturally occurring element in many water sources. Some have too much and some not enough. The idea behind community water fluoridation is to keep at at the optimum level for strong teeth when teeth are developing in children.
No. The small amount of Fluoride in drinking water will not have any other effect on your teeth. To much systemic Fluoride prior to age 6 can cause dental fluorosis (mottling) on the permanent teeth. Care should be taken that children who live in areas with Fluoride in the water not receive to much Fluoride from additional sources.