I'm interested in reading some of the JSA story lines that are highly regarded. The series seems to be one that keeps a steady following and ardent followers. Are there any recommendations? I know there was a spinoff/prequel(?) to Kingdom Come. What others would be good starting points/beneficial reads?
You can try the first 25 issues of the Goyer, Robinson, Johns run from the early 2000s, it established the new incarnation of the JSA.
Pretty much the entire JSA series is great and the early part of the follow-up Justice Society of America title was also really good, although the book floundered pretty badly after Geoff Johns left. Unfortunately it had just started getting good again when the relaunch happened. The first four issues of JSA Classified are must-reads - those are the books that made me a fan of Power Girl, the JSA, and DC comics in general. And Kingdom Come's follow-up was called The Kingdom, if I remember correctly. It fleshes out some of the new characters like Iris West and Nightstar, but other than that I don't think it was particularly memorable. It certainly wasn't on par with Kingdom Come itself. I think it also introduced the idea of Hypertime, which never really went anywhere.
You should check out "JSA:The Golden Age". Doesn't quite have the same feel as the later JSA, but it's pretty fantastic.
In my opinion, it crashed and burned badly when Marc Guggenheim took over. I couldn't stand the Supertown arc, so the relaunch cancellation of the book was a mercy killing. The book is supposed to return, set on Earth-2 as it was before the Crisis. I hate that all the modern era JSA stories "never happened" in the DCnU, but I agree generally that the JSA series was good, what I've read of it, and the follow up Justice Society series was also pretty strong for a few years.
The problem is Dc is escentially loosing almost all their legacy characters and resetting most things to mid 70's early 80's style continuity. With the guardians being the dicks that they are for instance, I always thought it would be cool if Alan died and Hal got his ring, one the guardians couldn't take away. Which of course now can't happen.
Yeah it really started to lose its focus on being a "family" of heroes as opposed to the JLA's task force. DC has real difficulty finding writers to follow up on strong runs. Teen Titans, Flash, JSA really struggled after Johns left, and Brave and the Bold after a good run by Perez and Waid really plummetted afterwards.