I agree with Lynn's recommendations. I especially love All Star Superman. It's a great story. Another non-cannon story I really like is Superman: True Brit. It's a comedy co-written by John Cleese.
I don't know how readily available it is, but there is a collection of early '90s stories that's titled Lois & Clark: The New Adventures of Superman. It has a photo from the show on the cover. It has a few stories that are in a similar vein to the show. It's a fun read.
Most of my collection is Silver Age comics and collections of Sliver Age comics. I love the silly stuff. But, like Lynn mentioned, you have to take it in context. I love the Superman's Girlfriend Lois Lane series that ran from the early '50s to the '70s, but it gets pretty sexist.
I really recommend Superman/Batman: Public Enemies. They made it into an animated movie, too, and it's a pretty good adaptation. I like the relationship between Superman and Batman in that story. They are best friends, and it feels genuine. (My signature is a quote from this story.)
Again, I don't know how available it is, but Under A Yellow Sun: A Novel by Clark Kent is a good story. It's a short trade, and it's very Clark-centric. He's writing a novel, and the novel parallels what he's doing as Superman and how he feels about it. It's fairly introspective, and it shows Clark thinking about the morality of what he's doing and the best way for Superman to act.
