Warren's The Spirit is the series that really introduced me to the character. The single story in The Great Comic Book Heroes didn't really give me a true sense of the fun of Will Eisner's creation.
But Warren got into the show after Kitchen Sink revived the character in two very handsome issues. I love the slightly raw and slightly naughty covers on these.
After Warren's run, Kitchen Sink once again took up the series and it ran in magazine form right through the 80's and in comic book form into the 90's.
I need some time I guess to actually get the Spirit archives, but having the complete Kitchen Sink runs, it seems a bit redundant at this point.