Im not aware of Pakistan's judicial system but I dont think he should retire. He was reinstated so he probably wants to stay on for a while.

PS- What the use of a court system for a country without a constituion? Thats the first thing we need for a stable govt.

just my oppinion.

whats urs?

Well my reason will be that he had an open confrontation with the establishment including Prez, PM and almost all govt minister. His every decision will now be viewed in light of that no matter right or wrong decision, He is certainly aware of that n as humans tend to do might overcompensate to appear as non biased. I think the point is made the Judiciary from now on is independent. Why bring disrepure or shadow of doubt on Supreme court. He won and should resign for the larger cause.
As far as the Constitution goes, which one? the one passed and implement in 1973 wasn't the best either. BUt its a start, the constitution is not suspended its just have ammendmends made which all political parties backed in the parliment under Musharraf so as far as constitution implementation goes its implemented