I absolutely enjoyed Smallville from its inception, until the final episode of season 10, and own all 10 seasons on DVD. I also continued to read the collected Smallville season 11 comic, which while a very enjoyable read, the artwork sometimes disappoints. The meeting of Clark and Bruce Wayne was particularly well done.
I, like many here, was surprised that Warner did not translate Smallville directly to film, and instead chose to reboot the Superman movie mythos with Superman Returns. IMO, Michael Rosenbaum is the quintessential Alexander Luthor.