I always liked Alan Simpson, a pragmatic conservative former senator from Wyoming. He voted for Don't Ask, Don't Tell - and now he's for dropping the ban entirely. He justifies this shift in part by emphasizing our need for "every able-bodied, smart patriot to help us win this war." He emphasizes, too, the ongoing changes in society's attitude toward homosexuals in the military; for instance, the "percentage of Americans in favor [of dropping the ban] has grown from 57 percent in 1993 to a whopping 91 percent of 18- to 29-year-olds surveyed in a Gallup poll in 2003." That's an amazing figure. He even says that General Pace's recent comment that homosexuality is immoral was "completely out of the mainstream of American thinking"; I wonder how true that is, although it unquestionably describes the trends.
Plus, Andrew Sullivan has a link to some pretty surprising poll numbers on the issue, some of which Sen. Simpson mentions.