Okay, so Saint-Nazaire is not exactly at hot bed of culture but you'd still think that they'd have at least one good hotel.
We stayed at Au Bon Accueil, a relatively small 3 star hotel located on a quiet side street of town. The rates were reasonable but there were a few problems; one being the beds were terrible - incredibly uncomfortable and seemingly well past their expiry dates. Their double beds were far too small for two people, two adults anyway, and their "breakfast", which one would easily assume was included in the price based on how it was presented, was an additional cost and significantly above its value.
The shower floor was also quite interesting - so angled was it that I really had to struggle to manage to stay upright when my feet became soapy.
Would I stay there again - no way. Although there may not be much choice if I had to stay there again I'd pick the hotel near the train station.