I took the SAT three times and each time I did better in a different section. When I took the SAT in 2005, it was based out of 2400 and I ultimately ended up with scores of 1750, 1770, and 1770 - though my best scores from each section yielded an 1830 - and I was happy with that.
With that said, I also wanted my score to reflect well to colleges, which is why I took it multiple times. After the third time though, I realized that my scores were not changing by much and spending the money to take it yet again in an effort to get closer to perfect would be fruitless.
If you take the SAT and do well the first time (score of 1250 or above is considered "above average" or in the top 20th percentile), most schools that consider the SAT in their decision would consider you an eligible applicant. If you score below an 1150, it might be worth it to take a second time (after some prep).
Keep in mind that the above is not an "end-all-be-all" rule. Some schools do not consider your SAT score in their decision at all. Some may weigh more heavily on your academic career, or your essays, or your extracurricular activities. And on the flip side, some schools (Ivy Leagues and prestigious universities that are highly selective) may expect higher scores.
So whether you take it again is ultimately up to you. How you feel about your score the first time, if you were prepared to take the test or if you think you would benefit from studying and taking again, and what kind of school you're hoping to go to may all influence your decision to take it more than once. And it certainly can't hurt.
Hope this helps a bit you analyze your decision a bit more fully. Good luck!