HDTV sets are available from as small as 15 inches to a whopping more than 70 inches. This measure is diagonal, corner to corner. The modern HDTV screen is less tall and more stretched out than older TVs, so you will probably want a larger screen measure than you have now. A 27" HDTV screen would feel much smaller than an older 27" TV. To maintain the feel of the size in this case, you would probably want to go to a 37" HDTV set. People would be about the same size on both examples.

Here are several more size considerations:

If your average viewing distance is 7' or less, look at sets 37" or less.

If your distance is 9' or more, sets 42" and up should do the trick. In between, 7' to 9', 37" to 40" should work.