I've been watching Smallville on off. Before it came on TV, I was hyped for it! I was experiencing serious withdrawal of the Lois and Clark series (and I'm still an avid part of that fandom). But this is probably why I've always looked very critically at Smallville. I had expectations, and that's usually a bad idea.
I good get right into it, starting with the fact the Kristin Kreuk is cute and everything, but Lana Lang is supposed to be a blond!!! And from there I could go on endlessly about things that fit the concept of the show, but not what it should be like in my mind.
Besides that, the series drew me in and I quickly became a great fan of Chloe's. I liked and like her much more than Lana. (But I've only seen season 1, almost nothing of season 2, and half of season 3).
All in all, Smallville didn't live up to my expectations, but I can understand why people like the show so much. If I hadn't seen Lois and Clark before that, I might have love Smallville to pieces. Who knows. (And I admit that Lois and Clark wasn't the most genial series ever. But it had the romance and the chemistry)
As to if Rosenbaum is the best Luthor ever or not... I disagree, John Shea did a job that nobody will ever manage to get close to. I tried watching Mutant X where he plays the good guy. But I always thought he would turn around at any moment and stab the mutants in the back. He's the bad guy for me. Forever. He can view that as a compliment.
Ok, I'll stop rambling now. Please don't kill me.