If you don't have a cable box and are with Cox cable you don't get any HD channels. You can get HD signals off the air if you are close to towers. If geting signals off the air(antenna) the TV will tell you what they are broadcasting in. If you have the Cox box, then you can recieve HD broadcasts but they are few. I have the Sammy 40" 720p LCD.
Yeah, I pick up a few HD channels such as ABC, FOX, NBC, and maybe CBS. That's fine by me for now because I can watch LOST on ABC (HD) and play my 360 which looks amazing!
the best thing to do is call ur cabel company and ask what the signal source is in ur area. I just did that today and I was told STD. I just purchased a samsung HL-T6187S and I am very happy with it. So glad I looked around and found a great deal on the google search. Good luck!!