Michael, I would have put up the link to the GCD several days earlier, but like you, I found it to be down all that time.
Although I love the Superman From the 30s to the 70s volume (and the Batman book; unfortunately I don't have the Shazam one), one thing disappointed me about it - the complete lack of Superman stories from the 1962-66 period, the high Summer of the Silver Age so far as Superman is concerned, in my opinion.
Since I got the book, I have nearly completed my run of the Action and Superman comics of that time, so it doesn't really worry me all that much now.
The Shazam volume is very difficult to locate. I still need to track it down at some point when I have the time and, more importantly, the money.
It's funny that you mention the lack of late sixties stories because I noticed the same thing when I was putting the list together. On one hand it looks like they were going for certain beats in Superman's history. The first issue of
Superman. An early Luthor story. Lois first suspecting Clark of being Superman. Luthor, Prankster and Toyman teaming up. The origin of Bizarro. Superboy's "first" day out. A time travel story. Then there are other times where they get kind of lazy. The stories from the '40s (sorry for the rhyme there) seem to be chosen out of a hat though there are certain themes that run through them. In the '30s to the '70s volume the sixites take up too much time with Bizarro stories.
Still and all these were the first Superman comics I can remember reading so they'll always be special for that reason.