If you have problems with your feet, I would definitely take a look at diabetic shoes and socks. Diabetic shoes are made to be seamless so their is no rubbing of the foot against exposed seams/edges. Diabetic socks are also made to be seamless for the same reason. I would ask your local podiatrist on his advise, depending on your foot condition.
If you have swelling, sometimes it may be difficult to find a sock that fits you. Take a look at the Extra Wide Sock that offers medical socks for men and women.