Hi Raggs:
The answer is "it depends". If you have an off-the-air tuner (usually called an ATSC or VSB8 tuner) it won't make any difference if you use cable. You'll still have to use their box to get their HD signals, which are broadcast in a different format, called "QAM".
If your TV has only an ATSC tuner, you'll be all set for off-the-air reception, but you'll have to put up an antenna. What you'll get depends on where you live and the antenna, but you can get a rough idea at:
www.checkhd.com Just put in your zip code and it will show you what over-the-air signals you might receive.
The Panasonic I got a couple of months ago had both ATSC and QAM tuners in it. When I hooked it to the cable (without the box) I got all the local stations twice. Once in regular def then, on a higher channel, in HD.
As PW pointed out, I only got a couple of the sub channels (mostly PBS). The ABC station has a continuous weather radar subchannel that you can see over the air, but I don't get on the cable. (No big deal since the cable has a radar channel.)
I got the HD box anyway for two reasons:
- I wanted the HD digital video recorder (like a Tivo)
- The box allowed reception of cable-only HD programming (Discovery HD, InHD1 & 2, etc.)
Since you're going use cable, just get a set you like. If it comes with a tuner, great. If not, no big deal - you can always buy an external one if you really need it later (down to about $160 now). (I really like the set I got and would have bought it without the tuner.)
Cheers,
Bob