Is there a difference in the quality/size/weight of the coax from the roof-mount dish to receiver compared with the receiver to TV connection? I need to extend the cable from the dish to another room and need to know if I need something heavier than standard coax. Thanks.

For 99% + of all installations - it's all RG6 for all cables.

Assuming you have SD boxes, RG-6 can be used throughout or composite/s-video between the receiver and TV, if you are running HD boxes, you'll need to use component/DVI/HDMI between the receiver and the TV.

From dish to receiver, use RG6.
From receiver to TV, for the best picture quality use A/V cables or S-Video. For HDTVs, use HDMI or component cables. Never use coax from the receiver to the TV, except as a last resort on an ancient TV with no other way to connect it.

Thanks, all. Yes, this is to get the receiver down a floor to a new LCD so I can use a higher-quality connection (right now the new TV is fed off plain RF signal via coax and, of course, the picture is lousy). I just need to extend the coax coming from the dish, so it's good to hear RG6 is fine.