Hi,
I was there last Dec for a day and a night. I did not have time to check out anything and since we were with some other friends who aren't gay, going out was not that high on the itineary. But I believe that the scene there would be rather small.. but with some rather cute italians around on the streets everywhere..
Well, advise would be to avoid the train station area, it was a mess and there were lots of "strange" people around. The area there really looked rather itimidating.
Of course driving there would not be recommended within the city it was a total chaos.. though fun to see especially during rush hours.. makes the famous Etoile roundabout in Paris looks like child play..
Second the trip down to Pompeii and the coast. Though one incident happened when I was in Pompeii.. was visiting the best restored building there, the Villa (can't remember the name), and guess what.. one of the security guy there was like trying to flirt with me and get me to follow him. It was so weird.. at that time I was seperated from my partner and this guy came up to me.. pretending to explain some of the fresco to me and took me from one room to another and each time trying to rub himself near me..

He was not that cute in anyway, but even though he was.. I was not interested.. luckily I managed to shake him off by mingering later with a group of tourist.. and later when I met up with my partner again, he told me the same story

Ok.. off topic.. back to topic.
In Naples I stayed at the HI in the business district. It was a nice hotel, was upgraded to an executive room with a nice view of the city and sea view.
Another trip will be going up Pompeii itself. Though I did not manage to get to the top at that time due to the layer of snow as we went up and the car we had I believe was not fitted with the correct wheels as it just slipped. A Fiat btw.
It would be great to have your own wheels for trips out of Naple self. We went to a small coastal town and had a really wonderful seafood and pizza. I think this is true for most of these coastal town.
Hope this helped.