The Northwood's slightly worse performance in encoding and some games makes it a tie, imo.
The heat, once again, is not really a factor at all, imo. The latest Prescott steppings are actually not much warmer than Northwoods, and even the early ones weren't anything a decent cooler couldn't handle. Not to mention when you factor in the heat the whole computer is putting out.
The extra power consumption is trivial in the overall picture, imo.