I would like to clarify a couple things...
If you are watching off of cable or satellite, the picture quality is out of NBC's control. They decode, then re-compress again, at who knows what bit rate. I would be interested in OTA picture reports, however.
Also, the big events (figure skating, speed skating, hockey, opening/close, etc.) are full NBC HD productions with a massive technical and HR investment. NBC has their own HD HD trucks covering these venues with a huge number of cameras, edit suites, and staff. It is a really amazing setup (and being a TV engineer, I'm not impressed easily), I'll post some pics if you are interested. They do tie into the host feed for extra cameras. The production gear is all HD-SDI. This is uncompressed digital HD and as good as it gets.
Out here, the programming looks great. I also know that the standards conversion for the main feeds is top notch, so I assume the poor picture reports are do to compression in the US distribution system.
They do use european production trucks, and a 50hz power system and lighting,.. so a 60hz production on this scale can't be done.
It's too bad to hear the pictures at home aren't that great, because it all looks perfect on this end.