Installation-CAT5 or RG6?

According to UVERSE, I can use CAT5 exclusively for connectivity to each receiver they will supply. As my house is new and has RJ11,RJ59,RG6 and Cat5 pre-wired to every room of the house where I'll have a UVERSE receiver.
I'm wondering whether it would be best from a video quality standpoint to use CAT5 instead of RG6.
Thanks,
Bruce

It is cat5 that is preferred. I have one STB hooked up with cat5 and two hooked up with coax. My feed comes in with zero errors, so the coax is not a problem, but they say if I were further away from the VRAD the cat5 would be better. For more info on my install see: U-Verse IPTV (http://www.highdefinitionblog.com/?page_id=286)