I was thinking about this last night and was thinking "OL" because of how good some middling RBs looked post-TD with that all-world OL the Broncos had at the time. But then I tried to think of whether I can remember an elite RB ever having bad seasons when his OL was average or worse. That's not my perception. I think they're close to equally important, but I give the nod to a RB doing more to elevate or downgrade a run game than an OL does.