I have never seen a print made on Azo paper so I don't know exactly what they are like, perhaps I should get some from Michael Smith for I have read a lot that he has said about the special qualities. I hope that what I am about to say does not offend anyone, it is certainly not intended to. I believe that making prints such as you describe, deep blacks long range, can be made on most GOOD quality papers and are likely to equal those made on Azo. Michael, if you read this I am not rubbishing your views.
I have been leading workshops on black and white printing in both the UK and to a less degree in the US for many years and have come to the conclusion that most of the problems relating to prints lacking in depth and sparkle is linked to selection of the wrong paper grade and the reluctance to carry out significant manipulation. Many people wish to make only a straight print on grade 2 paper.
I also think that many photographers are afraid of negative that show higher than normal contrast and believe that they will lose the highlight detail. Many of my prints are made from quite high contrast negatives and on higher paper grades, I often print on grade 4 and 5 and I do hold detail throughout.
To answer your question David, my personal choices are Ilford Warmtone and Oriental Seagull but I know that papers like Forte and Bergger also produce excellent tonal range. I am in the process of testing a new paper by Fotospeed called Elegance and the first quick prints I have made look excellent. I will report back in a few weeks for I am in the process of moving house and my darkroom will be out of commission for the next couple of weeks. I know you have my book and would point you in the direction of chapter 4 for guidance in using developers. I honestly don't think that there is a magic formula or combination of paper/ developer that will automatically produce the print. Your judgement is, in my opinion, the most important factor. Go into your darkroom and push the materials and yourself beyond where you have previously been, I promise you that your prints will improve.
I am a great fan of Paul Caponigro whose prints are the best I have ever seen so I will tell you a little story about him that inspired me. He was visiting Fred Picker who was having difficuty in printing an image of water where the water looked wet. Picker asked Caponigro how to make it look wet. Caponigro said don't come out of the darkroom until it does look wet and then he left. Picker was a bit upset at this answer for he wanted the magic formula, until he realised that Caponigro was saying to him keep trying different combinations and techniques until the water looks wet. Picker went back into the darkroom and several hours later made the water wet.