It is hard to find really good TV shows these days, if you're only looking on the major US networks. Good family TV shows are even harder to find! But the networks do still carry some good crime dramas for teens and adults, and even some good reality shows good for a family with preteens or mature intermediate kids. (such as The Amazing Race series)...and I've just discovered Lost, which doesn't seem to bad for the older family.
But looking at some of the other networks and cable channels, there are good shows to found. CBC carries some good family shows (like Just For Laughs gags) PBS has some good stuff: Are You Being Served (funny on so many levels), Keeping Up Appearances, the "House" series', and so much else. And then the cable channels have a myriad of good programming, including family educational shows, comedies, dramas, and vintage TV.
I have to say, though, that some of the "good old days" shows may be clean, but that doesn't make them that good. And some of them are clean on the surface, but actually rather rude and derogatory. Although, certianly, there are lots of shows from "the good old days" which are actually great: The Cosby Show, Columbo, Murder She Wrote, I Love Lucy and The Littlest Hobo, etc.