Let's see if my FAQ on this subject prepared for another forum, updated with all the latest sources except this latest New York Times link that robg has kindly posted here on Hacker News, is of interest to readers here.

ONE-TIME TEST-TAKING

Colleges have given up trying to distinguish one-time test-takers from two-time or three-time or even four-time test-takers, because that wasn't useful information to the colleges. There are a number of reasons for that.

1) The colleges have utterly no way of knowing who spends all his free time practicing taking standardized tests and who takes them "cold."

2) The colleges are well aware that students who have actually taken the tests sometimes cancel scores, so they have little incentive to give students bonus consideration if the students submit only one test score.

3) The colleges are aware that students who take the admission tests at middle-school age, who are numerous, do not have their earlier test scores submitted by default.

http://www.collegeboard.com/student/testing/sat/reg/circum/y...

http://www.hoagiesgifted.org/talent_search.htm

http://www.tip.duke.edu/resources/parents_students/interpret...

4) Colleges are aware that the majority of students who take the SAT at all take it more than once.

http://professionals.collegeboard.com/profdownload/Avg_Score...

5) Colleges are in the business of helping students learn, and they don't mind students taking efforts to improve their scores. They know that students prepare for tests.

From the New York Times: "Although coaching would no doubt continue if subject tests replaced the SAT, at least students would be focused on content as much as test-taking strategies, Mr. Murray said. There would also be pressure to improve local high school curriculums so that students were prepared, he wrote.

"These arguments make sense to Mr. Fitzsimmons [dean of admission at Harvard], who said, 'People are going to prepare anyway, so they might as well study chemistry or biology.' He added that 'the idea of putting more emphasis on the subject tests is of great interest' to his group."

http://www.nytimes.com/2007/09/19/education/19sat.html?pagew...

6) And now the College Board is back in the business of letting students choose which test scores to send into colleges,

http://professionals.collegeboard.com/testing/sat-reasoning/...

so now there is less reason than ever to suppose that colleges care how many times you take the test, because the colleges have no way to know how many times you took the test officially.

Colleges treat applicants uniformly now by considering their highest scores, period.

http://talk.collegeconfidential.com/parents-forum/349391-ret...

http://www.admissions.college.harvard.edu/utilities/electron...

From the Harvard admission office: "If you submit more than one set of scores for any of the required tests, the Admissions Committee considers only your best scores—even if your strongest SAT Subject Tests or portions of the SAT Reasoning Test were taken on different dates."

See also a Newsweek article about the renewed score choice policy adopted by College Board.

http://www.newsweek.com/id/172585

Some colleges want to see all scores a student has ever obtained, period, but as one admission officer asks, if "a student submits a single best sitting of 2320," does anyone really care "how low were her other score sets?"