Well, regarding Sauron being able to put aside his Ring (Númenor), that strikes me as, in a sense, a case of self-mastery. The Ring, after all, IS Sauron. It's his essence that is diffused through it, and which gives it its power. It occurs to me that there might a sort of analogy that could be made with addictions: for anyone else, there are physical side-effects of withdrawal, since a foreign substance (object rather) that the "user" has become accustomed to having has been withdrawn (or willingly given up, as in Bilbo's case), as well as any psychological trauma, but in the case of Sauron it seems much more like giving up a habit, because insofar as the Ring is an extension of himself, he's really just stopped using that part of himself--the distinction here being that Sauron has stopped using something natural to him (natural in a sense anyway), whereas any other Ringbearer is having to stop using something that is not natural to him--a foreign substance, so to speak.
I do stress, however, lest the topic go that way, that I do not see the Ring as an allegory for drugs so much as drugs being a useful allegory for the Ring.
