First of all, Green Lantern (Hal Jordan) is my favorite superhero of all time, bar none. Ever since I was a little nerd I wanted a power ring. Now that I am a pushing-40 nerd, the recent revival of GL is awesome.
I have a friend who has picked up GL, and this blog is for him.
You need to collect two books: Green Lantern and Green Lantern Corps. These two books are very closely intertwined, and when there is a crossover, they continue into each other.
I will give you the mega-quick version.
Way back in the 90's, DC sucked, and made Hal Jordan (pictured) go batshit crazy. He killed fellow lanterns and became the villain known as Parallax. Why did he do this? He was distraught over his home town, Coast City, being blown into oblivion by the alien Mongul during the whole Reign of Supermen storyline (after Supes died). A little odd, considering how grounded Jordan was just the issue before the new "creative" team took over.
Anyway, the Corps was gone, all that was left after Hal killed everything was a guardian who gave the ring to an earth-man, Kyle Rayner. Kyle was written like a Spider-Man type everyman. I call this "The Stories We Shall Not Speak Of".
So Hal, as Parallax, enjoys a run as one of DC's villains, acts like an ass, and finally redeems himself by reigniting the sun in a (forgettable) mini-series called Final Night. Yay, Hal dies a hero. Excuse me while I go puke.
Hal then serves as a host for The Spectre, God's spirit of vengeance. In Hal's case, he becomes a spirit of redemption. After Hal's Spectre series gets canceled, the way is paved for Green Lantern: Rebirth. GET THE TRADE PAPERBACK NOW.
Long story short, excellent mini-series, with Hal ditching the Spectre (or getting ditched) and returning to life. He also flattens Batman with one punch when Batman was being a hardass (their relationship soured after Hal turned bad). This also showcases the return of Sinestro, former GL, and current cold-blooded nutjob. What of Parallax? Parallax turned out to be the yellow impurity hanging out in the central power battery, where all GL's powers come from. Kilowog (former GL) becomes a GL again, and along with Jordan, Kyle Rayner, John Stewart, Guy Gardner, and Kilowog (I hope I am not missing anyone), they take care of Parallax.
This paves the way for the return of the Green Lantern monthly, and the Green Lantern Corps mini-series "Recharge", which brings back the Corps.
Key books to read, ALL OF THEM. Okay, at least The Sinestro Corps War. Unbelievable story. Also the Year One arc, as it has implications going into the current Blackest Night storyline. Now there are multiple-colored lanterns encompassing the color spectrum...Blue for hope, Red for rage, Yellow for fear, and so on.
These are, in my completely biased opinion, the best books on the shelves.
Next up, dumpster diving into Deathblow #1 and #2.