Don't put your SAT score on your resume (I'm assuming we're talking about MBA/business school resumes). Banks, consulting firms and other recruiters will ask you for your SAT score if they are interested. Typically, they do this when you fill out their application form. Many of the big recruiters track their applications via an online system. The process typically starts with firm presentations on campus. At some point, they will narrow down their list, and then later come out with an interview list. Generally, at some point once they start culling the herd, they will ask people to fill out an online application form. A lot of the firms pre-fill forms with information from your resume. If they want yoru SAT, this is when they will ask for it.

You might want to put your GMAT score on your business school recruiting resume. The convention seems to differ from school to school, but the rule of thumb seems to be that people include it when they are over 700 or over their school average. Some schools discourage including it at all, while others have it as a standard part of their resume template. Going back to your original question, a 99th percentile GMAT could definitely give you boost with most banks (and consulting firms).

I wouldn't put in on a resume, I would just tell them if asked. A lot of banks have a form you need to fill out for them and you will need to include gpa and gmat on it anyway. If I got a 95%+, however, I'd put it on.

Well, it depends. It depends on which school you are at, which industry you are looking at, whether taking it again will affect other aspects of your application and/or life, what your expectation is of getting a higher score, what's your cash situation and so forth.

If you're looking at banking or consulting, it's definitely nice to have a score above the average. Probably doesn't matter for most other industries, although highly competitive firms in other areas do look at GMAT scores (Google is a good public example, and many PE/HF shops love high scores).

There's probably a sliding scale between the reputation of a school and competitiveness of the firms you are interested in. If you're at Harvard, you probably don't need to worry about your GMAT. If you are at an elite school and looking at Big 3 consulting or BB banks, it would behoove you to do what you can to make yourself stand out. I'm not sure I would 100% take the advice of a Stanford student if they told me GMAT doesn't matter in recruiting. Sure, not for him, but what if I'm not at Stanford? Same thing applies to different industries. If someone tells me their GMAT never came up in recruiting, I'd wonder if they looked at Big 3 or BB. At lower ranked schools (below elite), an ultra-high GMAT is probably one of the only ways to get traction at some of the more competitive jobs.

But, people have other things to worry about too. If you need to spend 500 hours preparing for the GMAT in order to improve your score, it would probably be better to do something else. Don't re-take if it will affect your other stuff.

Make your decision keeping in mind that depending on your school and target industry, a high GMAT score can help you get some of the more selective jobs.