Skill > Gear.
True, up until Outland. Once the gear inflation starts, gear starts overtaking skill.
That said, back in LK when I was 79 (in the feral pvp blue set), I killed an 80 rogue in full epic pvp gear TWICE (got the opener both times) because he was unable to compensate for a Free Action Potion.
f2p thread
Skill > Gear.