http://www.monoprice.com/products/product.asp?c_id=102&cp_id=10235&cs_id=1023501&p_id=2178&seq=1&format=2

http://www.monoprice.com/products/product.asp?c_id=102&cp_id=10235&cs_id=1023501&p_id=2776&seq=1&format=2

My question is if I really need to go with the premium cable at 50'? This will be going from a D* HR21 to a 720p HDTV.

Go with the RG6.

The RG6 is likely worth the extra money. We spend so much on high-quality equipment to get the best picture, why compromise the picture with RG59?

Using RG59 with high-end HD equipment is like buying a high-performance muscle car and putting cheap, scrawny tires on it.

1 5/8" heliax should work great

I don't think you will see a difference, but at 50' I would spend the extra money just for the "peace of mind" factor.

Spend the extra money - Monoprice's prices are so cheap anyways.

Component video only goes up to 37Mhz, I doubt you'll see a difference.