Row 7 or 8 for me.

For me the legroom is enough, I don't need to be in 17. I get to get off the plane a little bit faster.

Row 6 has the tray tables in the arm rests so the seat is narrower. Row 10 on the -800 has the risk of losing PC if your flight has an equipment swap to a -900. Row 10 on the -800 and 9 on the -900 (and row 17 on both) all have someone in a standard Main seat behind you, which in my experience increases the chance of a small child who likes to kick the back of my seat being seated behind me. Similarly, I prefer PC over row 17 since loud upset infants are likelier to be further to the back of the plane.