Yeah, I had major problems with this one. I was stuck with the ring. He was hanging around his cell as a
werewolf and I couldn't get in to kill him. I took somebody's advice to conjure a flame atronach behind him and drive him to me, then dagger him at the cell door. The idea was that it wouldn't stagger him back. Well, he staggered back...
I went out and found, killed the stag. Hircine showed up but wouldn't talk, and I couldn't get any dialog menu with him. I tried reloading and rebooting and everything else, but nothing worked.
I finally read about the basket/kettle glitch somewhere. It wasn't a detailed explanation and I had to do some experimenting with it, but it did finally work for me. (PS3 with 1.5 patch I think)
Basically, you go to the jail with two baskets or kettles. I had one of each, all I could find in Breezehome...in retrospect, it would be a good idea to have 3 or 4 of each, just in case. Kill Sindig in the cell, so he can't get to you and kill you. Conjure something in there with him, and light him up with arrows or spells.
When he's dead, stand in front of the cell door about 5' back. Take a basket out of your inventory and throw it on the floor. Then point at it and hold X, like you do when you want to move something aside. Very slowly and gently, use your right stick to raise it to eye level in front of you, then still holding it, use your left stick to walk slowly toward the cell. If you do either too quickly, you may drop it. Once you're touching the cell bars with the basket at eye level, it should rotate so you're looking into it. When you can just "feel" the resistance of the bars, and see a little bit of the bars through the bottom of the basket, keep holding it there and whirlwind sprint into the cell. The basket will probably stay on the free side of the bars, which is why you want more than one.
The guard will probably ask you to stop shouting...just tell him it won't happen again.
Now you're in the cell with Sindig's body. Search, and it should give you the "skin" option. Skin him, and Hircine should appear and give you the savior's hide. There was all manner of discussion about how to get both the ring and the hide, two rings, etc., but I was just happy to be rid of the damn thing and out of this quest. Repeat the basket trick to get back out of the cell. Tell they guard you're sorry, and be off...free.