Personally, I do not think that snakes possess any kind of intelligence that is on a par with, say, cats and dogs. However, retics are pretty alert and inquisitive compared to other species and, in that context, may be considered as being more "intelligent."
::I've seen references to retic intelligence from time to time. Not owning a retic yet (but will very soon) I'm very curious about what you mean by "intelligence." Apart from a keen sense of knowing when there's food around, what else have you observed?