As some others have mentioned, I like my scope to be as close to the barrel as possible and use low rings. It is just hard to beat a 3X9X40. I have always felt that any additional light from a 50 is more than offset by the weight and less than perfect head position required. Besides, a high quality 40 will provide as much or more low light transmission than a lesser quality 50, and cost about the same.
If you Lie, lie to save a friend.
If you Steal, steal the heart of a beautiful maiden.
If you Cheat, cheat death.
And when you Drink, drink with me, my friends.

Molon Labe!