In my opinion, the SD feed of NBC is the worst of the us network. But in HD, it's quite good. The Olympics, the Today Show, NBC nightly news, Jay Leno all look great in HD.
The Sd picture of cbc and radio-canada is very good in SD and even better in HD. It always blows me away to see that most shows on RC and CBC are in HD. I guess when the taxpayers are paying, there is no limits.
On the big US networks, a lot of the big shows are not in HD, which is weird.
The SD picture of HGTV and Food also look great, in SD.