Yep, I have to agree with stuey here. I Have been using Houx for the last 4 years, and it is my preferred site. As stated, the pitches are premarked and numbered, so no worries about when to arrive, the toilets and showers are kept clean and, apart from usual rush hour periods, normally OK for access. It is only a 5 minute walk to the pit village, and contrary to what Dave H says, it's not too far to the champers bar (in fact a damn site nearer than MB). It is not too far from the Houx Annexe/Technoparc roundabout mayhem and doughnut display (with complementary drive through carwash) either, if you like that sort of thing. If you know the roads well, it is deffo the best place for quick and easy access to town for shopping on busy race days, or to head on out for the compulsory visits to Arnage and Mulsanne.
Do not forget to take an assortment of electrical adapters if you wish to make use of the supply (yep we take two fridges to keep the beer cold). They can vary, but I think the actual adapter is like an external caravan or boat plug, ie a big round push in three pin thing.
The only major downside as far as I am concerned, is that there are no instant viewing areas for the race as you will find in MB.