But where are Breaking Bad and Arrested Development!?! This list was made in 2002 so those shows didn't exist yet.
From Wikipedia: "TV Guide's 50 Greatest TV Shows of All Time is TV Guide's list of the 50 most entertaining or influential television series in American pop culture. It appeared in the May 4–10, 2002 issue of the magazine, which was the second in a series of special issues commemorating TV Guide's 50th year. The list was also counted down in an ABC television special, TV Guide's 50 Best Shows of All Time, on May 13, 2002.
The 50 entries, chosen and ranked by the editors of TV Guide, consist of regularly scheduled series spanning more than half a century of television. TV movies, miniseries and specials were not eligible."