3970J + 3940G for sure.
In fact, I have a 3970J... and a 3940P. Not quite the same, I know, but for the reasons dr kol stated, 3940 is just such a classic piece.
Also, the 5970J is a beautiful, beautiful piece but for me - and this is a highly personal thing - the track kind of clutters the dial a bit. On the plus side, it does give it a "sportier" look. It is also a bit bigger so for those with larger wrists they may prefer the 5970 versus the 3970. However, I prefer the 3970.