I suppose a turn to the dark side was inevitable. Even if you're not familiar with the comics story, he's still called Sinestro for pete's sake! Also, he's played by Mark Strong, who did a fairly good turn as a good guy here but is just so much more perfect at oozing menace in films like Robin Hood & Sherlock Holmes.
Here's my ranking of the 4 big summer movies I've seen so far:
1. X-Men: First Class. It's been a long time since I've been this excited about a movie this good.
2. Thor. Unremarkable but with a lot of fun performances, particularly from Chris Hemsworth, Kat Dennings, & Clark Gregg.
3. Green Lantern. It's not as good as Thor but it's kind of on the same tier.
4. Pirates of the Caribbean: On Stranger Tides. It just totally smacks of disinterest and a deliberate lack of effort.
Ranked among Martin Campbell movies, it's quite a disappointment considering this is they guy who gave us Goldeneye, Casino Royale, & The Mask of Zorro.
Ranking it among comic book movies, there are 3 tiers:
TOP-- This is where I put excellence, both universally acknowledged excellence--like the Tim Burton & Chris Nolan Batman movies, Spider-Man, Superman, the 1st couple Blade movies, & the 1st couple X-Men movies--as well as overlooked gems like Constantine, Daredevil, Superman Returns, Teenage Mutant Ninja Turtles (1990), TMNT (2007), & V for Vendetta.
MIDDLE-- This is where Green Lantern goes, alongside other fun diversions like Iron Man, Iron Man 2, Thor, Hellboy, The Crow, Superman II, Teenage Mutant Ninja Turtles II, and, on a good day, mediocre sequels to greatness floating on the good will of the originals like Spider-Man 2, Spider-Man 3, X-Men: The Last Stand, & X-Men Origins: Wolverine.
BOTTOM-- Of course, there are several levels of Hell, ranging from stuff I absolutely despise (300, Sin City, Superman IV, The Punisher (Tom Jane or Dolph Lundgren versions)) to tragic misfires (Watchmen, Superman III, anything with Hulk or Fantastic Four in the title) to guilty pleasures of mine (Elektra, Ghost Rider, Blade Trinity, Batman Forever, Batman & Robin, Teenage Mutant Ninja Turtles III).