In general, the higher the loft the better out of the rough, a 7w is a higher lofted club than a 2h.

Which one you hit the farthest will depend on you.

I have another post pending but, to reiterate, my personal opinion of a 7 wood is that it is probably the greatest thing since sliced bread. I find a 2 or 3 hybrid very difficult to hit and they don't quite get the distance a 7W does. A 7 wood has to be about the easiest fairway wood to hit and it hits off of just about any lie on the golf course. Great for tee shots on narrow fairways and getting on the green on long par 3s. It is a very workable wood and you can hit choked down shots and stingers with ease. The difference in distance between it and a 5 wood is about 5-7 yards. You can also toss the 3 iron and leave room for extra wedges in the golf bag. A 7 wood and a 24-26 hybrid are a pretty lethal combo in the golf bag. Furthermore, the 7W has that "knock the snot out of it" factor that a 2-3 hybrid doesn't.