Jeddah has 70 Km Cornische (Seaside) on the Arabian Sea, its like a fiesta everytime of the day and everyday in a year, it has so good Taxi service and spread of this city is around 400 kms roughly, people are so well behaved and nice and there is no fear at all of anything , anywhere, its so well planned just cruising around the city in a vehicle is pure pleasure see the most beautiful round abouts and such wide roads and overbridges and so many super malls for shopping, you have all you want : scuba diving, joy rides, water skiing etc., even a female can go around the city alone any time of night and day without any apprehension of any danger, be it foreigner or national.
I personally will rate Jeddah with all its amenities better and far better than say reputed city like Dubai etc., its cheap too.
The best places in it are around the seacoast and its green too no traces of desert as is the common perception of people about Saudi Arabia. Just can be a very renewing , Calm vacation to visit jeddah for few days out of your everyday orbit.