Do you really need to own a car in Dubai?

Hi everyone - I am planning on moving to Dubai in the next couple of months. My work will be in downtown Dubai - I am not quite sure yet if I will get an apartment in Downtown or Dubai Marina/Palm Jumeriah.

I was just wondering if you really need to have a car in Dubai or if you can get away with just using the public transport system there?

If so, is the metro/bus/taxi systems reliable and are they costly?

Any views would be much appreciated.

Thanks

Vishal