I went from an LG 50" Sams' Club special in 2010 to a 55" Panny TC-P55GT50. I can appreciate the difference. I only sit about 7-9 feet away from the TV. If you sit further, and have the room, and the money, go for the biggest size you can afford.
The only reason I didn't want a 60" TV is because I get distracted when I can see the holes in the facemask of a 60" TV from such a short distance.