I'd like to have gotten to know pre-Azkaban Sirius, and also would like to have been there while he was on the run and in Grimmauld Place to help him through his troubles.
I'd like to ask Patricia: you said you wondered why Sirius thought he wasn't strong enough to be the Potters' Secret Keeper. I thought he said in PoA that his thought his being Secret Keeper would be too obvious so he talked them into using Peter. It didn't sound to me like he didn't think he wasn't strong enough, after all he said he would have died instead of telling. Do you have a place that said different?

Ebonystar

I would like to know more about schoolboy Sirius, his pranks with James against Snivellus, how he met his friends, if he had a girlfriend (of course I was that lucky girl...) etc...
I would like to see pre-Azkaban Sirius too, to know how he reacted when he found his best friend and his wife dead, what he did after leaving school, where he lived and...well...everything about his life!

I'd like to see more of home-leaving Sirius and adult Sirius pre-Azkaban. I would like to see the events that influenced Sirius and why he became the person he is post-Azkaban. I'd like to see what happened for him to leave home, more of his relationship with his brother (although that may be more teenage Sirius) and what his life was like when he was living with James. When he was an adult before Godric's Hollow happened, I'd like to see what his job was, how his friendships with others were, and the struggles he faced because of Voldemort coming to power. I suppose I'd also like to see more of his relationship with the Marauders at any point.

Certainly the reckless pre-Azkaban hotness of him.

The most? Ooh, that's tough. I like the different sides of Sirius for different reasons because he is such a complex character its really interesting to see the different aspects of his life that contributed to his personality--that's what I like the most about Sirius--he's realistic. He's not perfect, and he's not completly horrible--he changes as his life changes.

But as for what I would like to see the most, I would have to say that I really would like to see the Sirius after Hogwarts, but before Azkaban. We've seen a bit of everything else, and I would really like to see how Sirius reacted to the first war.

Something else that would be interesting that we haven't seen (and I really don't think we will) would be Sirius before he went to Hogwarts in Grimmauld Place. I think that would be really interesting to see how Sirius acted before he was sorted in Gryffindor.

Well, personally I like Hogwarts Sirius. I have NO clue why, I just like it most...
But unfortunatly I doubt JKR is going to give us any of that, so pre-askaban would be cool, too!

I don't believe they are still keeping a tally on this topic but I will put my two cents in anyway. I am in agreement with a lot of the posters that ANY information on Sirius would be wonderful but I must narrow it down. I think I would like to have more detail about the post-Azkaban Sirius. I am curious to know where he went and what he did to pull himself together after being in Azkaban for 12 years.

Coming in a very close second would be the adult, pre-Azkaban Sirius. There are definately a lot of unanswered questions attached to that time but, as the story was not written about James, it is perfectly understandable. It would be wonderful if JKR would decide to write a prequel some time down the line to fill this gap in (Alas, just wishful thinking!). Maybe she will address a little of this in the Dictionary.

Well, there you have it.

I would love some Sirius in his school days. I mean I know that all the seven books are out but one can still dream about the encyclopedia can't they? I want to see the antics of James and Sirius. I want to see what made them more serious and what brought about changes in their attitudes. I would also like to know why and how they joined the order. Lastly I want to know about their three year tryst with the order... I bet anything their fights would have been sensational and I can say this for them, neither would have used the "expelliarmus" curse as much as Harry!