Er... wrote:
I'm 5' 10 1/2" and 175. (50 years old.) I'm kinda hefty. Hoping I can get enough training in over the fall-winter-spring to run a half in late May. My ideal racing weight from many, many years ago--140 pounds--is totally unapproachable but I'm thinking maybe if I can get down below 160 it will be a big help in the spring. So yeah I wouldn't say 5 10 and 175 is fat but it sure ain't skinny around here.
I'm curious as to why you say getting close to 140 again would be totally unapproachable.
I'm 55 and the same height as you and weighed in at 165 at the beginning of the year after a long lay off from running. I've put in pretty consistent 50 mile weeks since April and have watched between-meal snacks and my weight is now 145 range. Running feels unbelievably better.
I don't see any reason you could not get well below 160 if you tried.
As for the OP and his initial comments - like others have pointed out, it just depends on what you want. 170 is not a bad weight, but you are posting on a board dominated by distance runners. When I weigh close to 170, I feel fat around my abdomen and running is definitely a chore. If you are happy with where you are at, sounds good to me. You are certainly in better shape than most other Americans.