ooh, my ears were burning 
I am indeed in KSA and am in Riyadh! I also have a young family (DC are 4 and nearly 2) so I guess I am the resident MN KSA expert
coccyx it really depends where you will be living. I live on a large expat compound but I have a friend here who lives in a villa in a 'normal' residential area.
Compound life is great for families. The compound we are on now even has a school and a nursery in addition to the 'normal' swimming pools, sporting facilities, supermarket etc.
There are of course a lot of restrictions when you leave the compound. Women have to cover up (abaya and headscarf) we cannot drive, cannot get pork, alcohol etc but you get used to it.
Quite often husbands come here for 6 to 12 months and then apply for their family to come out but I imagine it depends on the company. Certainly with DH's company there is a waiting list for wives and children to move out.
If you want more specific advice depending on your circumstances please feel free to PM me