Rex, obviously the design of the set should be one of the final considerations after you dish out all that cash for your set. So, hopefully the image is equal to all the others you looked at and the design was the last deciding factor for you.
But, from the specs, the Samsung looks like a good unit and should look great with HD cable. Standard definition stuff will likely look pretty bad, so get a good DVD player and your HD cable and hook it up before making any final judgements on image quality.
The fact that the TV doesn't have a built in HDTV tuner means very little as an integrated HD tuner would merely mean you need to put an antenna on your roof to receive HD channels that are over the air (OTA). Cable will likely give you the same channels you get OTA as well as a couple of premium channels and InHD which are not available OTA. Just make sure you use the component connections from the HD cable box to your set and make sure you are actually ON an HD channel. Probably channel 504 or something way up in the channel numbers. Ask the cable installer before he leaves if you are unsure.