Fox is whistling an extremely happy tune. Tuesday's two-hour American Idol debut averaged 35.5 million viewers, making it not only the series' highest-rated premiere ever and the network's best entertainment programming outing ever (ever, folks), but the most-watched entertainment telecast of any network since Friends' May 2004 send-off. ("Gigantic," "enormous," "colossal," "mammoth" and "gargantuan" are but a few of the words being heard in the Fox hallways this morning.) For the night, the "closest" also-rans were CBS' NCIS (with 17.5 mil) at 8 pm/ET and a CSI repeat (12.2 mil) at 9. Come 10 pm, NBC's Law & Order: SVU grabbed the helm with 16 million viewers, besting ABC's Boston Legal (11.8 mil) and CBS newbie Love Monkey (8.5 mil).