gonna go with the saints on this one.
although, the last time they faced a really good defense in the playoffs they got their ass beat (against chicago) despite the saints being a favorite and all the media "experts" picking the saints to win. I know it's not the same team, but they are close enough to make me uneasy on picking the saints.
49ers will have to play the perfect game offensively (no turnoevers, control the clock and run the ball very effectively) and defensively (keep the saints from scoring less than 24-27 points, which is obviously hard).