was a bigger issue in the early HDTV days especially with LCDs. You had lower resolutions and excessively large spaces between pixels (Screen Door Effect) that you did not want to sit too close to the screen lest you saw all of the TVs shortcomings.
With todays advances in the manufacturing process of making the spaces between pixels almost invisible, and the advent of the extra resolution goodness that is 1080p, it is encouraged that you sit as close to the screen as you can bear in order to see all of the extra resolution that you paid for.
The only real factor in seating distance today is how far is too far to sit from the screen where the benefits of 1080p are no longer apparent? This is a debated question that must also take into account screen size. There is no clear cut formula for determining what size TV you need at what distance to be able to tell 1080p from 720p. The only thing that you can say for sure is that the bigger the TV and the closer you sit, the more pronounced the benefits of 1080p become.
With a a 46" 1080p TV and sitting 7' away, you are definitely not too close to the TV (if you can sit closer and be comfortable, I would do it).
Whether you are too far away from the TV is something that is a little harder to answer.
But you are most likely at a "reasonable" distance.