1.) Chloe Sulliven & Pete Ross
Chloe Sullivan (Allison Mack) & Pete Ross (Sam Jones III) are both very close friends to Clark.
Pete has always been Clark's best friends since they were young. He does not know of Clark's deepest secret, but eventually (in the 2nd season), he finds Clark's spaceship & soon learns from the young Superman himself, that his best friend is not of this world. Chloe has grown to become close friends with Clark as well, and even has a secret crush on him, which (as the series progresses) slowly grows stronger. Because of this, her jealousy towards Lana is almost unbearable, but fortunately doesn't affect their friendship.