I don't watch Smallville religiously, so there are a lot of episodes that I've missed. I did see the Metallo episode though, and I thought that was really awsome.
I have a question though. I've also just recently seen the episode where Jimmy Olsen dies in Chloe's arms. Now it had been established in earlier seasons that Chloe is a "Meteor Freak" with the ability to heal with a touch. She brought Lois back from the dead with this power, although the effort nearly killed her. Did she lose this ability in one of the many episodes that I've missed? Or was her not using it to save the life of the man she loves just really bad writing on the part of the script writers?