We sat in the Right Field Roof Box 31 (Red Sox vs. Seattle Mariners), which I really liked. The seats are pretty high up, so we didn't feel quite as close to the game as grandstand seats would have put us, but we had a great view of the whole field, as well as Boston's downtown skyscrapers. For this area, which row you're in really doesn't matter: the seats are steep enough so that your view of the field is not going to be blocked when someone stands up in the row in front of you.

I also liked that the rooftop boxes feel private; it's a bit out of the way, so you don't have fans constantly leaving and entering your section. If that hasn't sold you on these seats, there's also a bar associated with the area which is much quieter than the main food areas. Overall, I'd definitely consider sitting in 31 again: it made the always jam-packed Fenway Park feel much less chaotic.
Onto the Fenway Franks...overrated. Their hot dogs and asking Sox fans to pay $6 for them is highway robbery.