Takes of the Unexpected...I personally didn't like it because I thought it ended up being kind of pointless. But your mileage may vary. It does portray very well -- probably unintentionally -- the ennui and and depression and resigned despair that Cris Allen was feeling in his role as the Spectre leading up to the events of Revelations.
John Ostrander's old Spectre series is pretty much the definitive take on Jim Corrigan, I believe. It's a good read if you can find it. Or. Y'know. "Get it." Somehow.
The miniseries Day of Judgment, written by Geoff Johns, details just how exactly the Spectre passed from Jim Corrigan onto Hal Jordan. If you're interested in that bit of the Spectre's history, it was actually a decent enough event.
If you want to know more about Cris Allen, on the other hand, I very much suggest Gotham Central. It unfortunately has nothing to do with the Spectre, but much to do with Cris. (and others)