On the last episode of Smallville we met the mysterious, rich, and very good looking (hey I am secure enough to say that) Oliver Queen, played by Justin Hartley. As many of you know Oliver is also known as the Green Arrow. By the end of the episode we see him firing his bow and from this picture we can see the green outfit. In Wizard they had a picture of his costume, it looked pretty sweet. Supposedly he is in Smallville trying to form a Justice League. The last episode had him having Lex kidnapped and testing to see if he still has the powers we saw from Zod's take over of his body. We also learned from Lionel that Lex and Ollie went to prep school together. In the Wizard interview, Justin says there will be a romance between his character and Lois, which could be quite interesting.
I am guessing he will soon discover Clark's powers and try to get him to join his new team. Which so far would probably comprise of Clark, Bart Allen (Impulse), Vic Stone (Cyborg), AC (Aquaman), and who knows who else. I have heard that we will probably not have an episode involving Bruce Wayne, even though it was hinted at before.
They should consider introducing the Martian Manhunter. He could be a cop from Denver who is known for being able to track any criminal (or maybe a U.S. Marshall, FBI type). Who comes to Smallville searching for some criminal and can sense Clark and wants to meet him, although I doubt the SFX money for Smallville would be able to make the shapeshifter look great, unless you have him as a human most times, and let him change to his green color once and then go back and say something like "my true form is usually too frightening for humans."