I think Cassillas is second best, closely followed by Cech. Iker just has those moments where he makes incredible saves from close range, his reflexes are excellent and because of that he has an edge over Cech IMO, a small one but still..
Hildebrand is playing an average saison with good and bad days. He is said to be haunted by Valencia and will possibly move there in summer since he decided to leave Stuttgart then.
Weidenfeller is awesome these days. One of the best Bundesliga GKs this season along with...guess who? Oliver Kahn who is world-class again.
yeah that's his name. And yes he's very good and very underrated. I will never forget how earlier this season he stopped 2 penalties in a league match in like 5 minutes apart. It was insane.
Buffon is sensationally good in the air. He punches the balls out of the penalty area or even smarter towards the corner flag instead of in front of the strikers.