It's official: Hit-starved ABC is on the comeback trail. Roughly 21 million viewers sampled the network's acclaimed new dramedy Desperate Housewives Sunday night, making it the night's most-watched program by a landslide and sending Law & Order: Criminal Intent to its lowest scores (possibly) ever. Housewives marks ABC's second hit of the new fall season; the net's castaway thriller Lost debuted last month to boffo numbers as well. Meanwhile, ABC's Practice spin-off Boston Legal won its 10 pm-Sunday time slot with 13 million viewers.