Not gonna lie it changes nearly everyday tho right now I guess it's Highway 61, I'm all over 'it takes a lot to laugh' right now, but like I said it changes all the time. His best though imo has got to be Blonde on Blonde, the amount of bangers in there is unreal
I suggest trying some of his newer stuff a listen too, they are not as bad as you would think. Time Out Of Mind especially is amazing.