Mykonos beach day - taxi or rental car w/kids?

We are a group of 8 including 3 kids who would like to spend some time at the beach in Mykonos with some time left over to visit town. We do not want to spend a lot of time searching for transportation (or getting stranded) after dragging kids to see ruins in other ports. Any advice on the pros and cons of taxi vs. car rental would be much appreciated as well as family beach tips.

We are a group of 8 including 3 kids who would like to spend some time at the beach in Mykonos with some time left over to visit town. We do not want to spend a lot of time searching for transportation (or getting stranded) after dragging kids to see ruins in other ports. Any advice on the pros and cons of taxi vs. car rental would be much appreciated as well as family beach tips.

http://www.greeka.com/cyclades/mykonos/mykonos-beaches.htm

We are a family of 3 (daughter 8) - we are touring the town in the morning from the new port pier in Tourlos by taking the shuttle to town (short distance) coming back to the ship for a lunch break and then going to the beach less than 1 km away (walk or taxi) Agios Stefanos - rated a family no-nude good sand safe beach in the afternoon

ShipOFools...thanks for the link. That is a great idea to shop first and beach later in the day.