"GREY'S ANATOMY - ""Dream a Little Dream of Me"" - On the two-hour season premiere of ""Grey's Anatomy,"" Meredith and Derek learn that ""happily ever after"" isn't easy, a military doctor who brings in a trauma patient catches Cristina's eye, and the Chief and his staff reel at the news that Seattle Grace is no longer nationally ranked as a top-tier teaching hospital, on ""Grey's Anatomy,"" THURSDAY, SEPTEMBER 25 (9:00-11:00 p.m., ET) on the ABC Television Network. (ABC/RON TOM)SANDRA OH"