720 - Should I take the GMAT again? Please help!

Hello Everyone,

I took the GMATs December 29th of 2009 and I got a score of 720 (Q47, V42). Although it is a fairly good score, 700+, I would really like to score in the 750+ range. I was hoping to get some advice on whether or not I should retake the GMATs and if so, how exactly I should go about improving my score. I have a very clear understanding of my strengths, weaknesses and the factors that may have affected my test performance which I will outline below to give you the best set of information.

Background:
I studied for probably about 2 months before taking the exam. I probably spent about an average of 5-6 hours a day studying and I used the follow materials to prep:
1. Manhattan GMAT Guides (All of them)
2. All the online Manhattan GMAT material (incl. all 6 CATs)
3. Power Score CR Bible
4. Every problem in OG12, Verbal Review and Quant Review
5. About 100-150 questions in the 1000 SCs document/webpage

Test day factors
1. One issue I had trouble with was that I was used to doing the verbal section by basically reading out loud to myself. Being able to also hear the words helps to increase my comprehension. During test day, I had to be much more quiet because there were other people in the room I didn't want to disturb. Due to this, I found I had to re-read portions of CR or RC.
2. Even with the problem mentioned above, I finished with a lot of extra time on both sections. I was actually having some issues finishing too early (poor pacing - possibly too much guessing when not necessary) and I put in additional effort to make sure I worked slowly. On the verbal section, I finished with probably 9 minutes left and I didn't really make any guesses where I wasn't stuck between 2 final solutions and I had exhausted all my methods to distinguish between the 2 answers.
3. On the Quant section, I finished with approximately 10 minutes early. I know this is a very bad thing. I tried working more slowly because I had the same kind of issue on practice exams, but in the end I still had extra time which I probably could have used to get more difficult questions right and a higher Quant score.
4. I was somewhat tired during the exam because the test was earlier in the day than I usually start studying.

Areas of Weakness
1. I feel relatively weak on Quant. I think in general, I am not super great a math so questions tend to take me a little bit longer to figure out. Also, when I first started studying, I was finding I was making a lot of stupid computational mistakes so I am a little bit slower with doing out the math to make sure I get it right. In terms of areas of weakness in Quant, I am basically the same across the board - perhaps a little bit weaker on tough word problems (work, distance, overlapping sets) and difficult inequality problems that mix in other stuff like exponents, absolute values, negatives, etc. I would like to get a Q50 if possible.

2. Sentence correction. I am solid on critical reasoning and reading comprehension. I have never been very good at grammar so it took me a long while to "catch up" to a respectable level. Even though I spent a majority of my verbal prep on sentence correction, I still missed significantly more SC questions than the other 2 types. I believe that my verbal score hinges on the "luck" of the number of sentence correction questions at the end of the exam - the more SC at the end, the worse my score will be.

Issues and Questions

Quant:
1. My biggest issue currently is that I don't know exactly how to go about improving Quant because I've exhausted a lot of the materials. I know I can find some additional materials, for example, the GMAT club tests - but will that be enough? The best questions to work with are the ones in the official guides and I have been over each one (and any that I've missed at least 3x.)
2. Besides feeling like I've already exhausted all of the most representative practice questions, how can I actually improve my Quant score? I followed every guide on this forum - Error Log, Figuring out multiple strategies to answer questions, etc but I still feel stuck. Should I just do more practice problems and fully review them, or should I go back and review more content? Do I need to just practice easy math to increase my speed? Should I do all of the above?

Sentence Correction:
1. There is a ton of sentence correction questions left for me to do - at minimum a few hundred 1000s questions. However, I feel like I got to the point where I plateaued on how much more gain I could squeeze out by doing more problems. I have a fundamental weakness in my grammar ability (at least compared to those who are able to get 99% in Verbal.) In studying for SC on the GMAT, I basically learned a lot of rules which I applied. (ex: If you see a pronoun, make sure it has an antecedent) At the end, I felt like my brain was a little bit saturated with different rules and as I continued learning new rules, I slowly forgot old ones.

I want to get a grammar book that is used for grammar in writing as opposed to grammar in GMAT test taking. Does this make sense? I'm hoping that by learning grammar with the intent of using it well in writing, I'll be able to learn it more deeply as opposed to just trying to memorize a bunch of "Don'ts". I know it will take more effort to do so, but I'm willing to put in the time. Does anyone know of any exceptional grammar books? This would give me a double benefit because I would also like to improve my writing ability.

Other:
Also, how are the other practice CAT exams? I won't be able to take anymore Gprep exams without getting a significant number of duplicates. I'm worried that other CAT exams won't give me an accurate representation of my score. Also, I've found that in the actual GMAT - getting questions right is much more important and the changes in difficulty when getting a right or wrong answer increment much more slowly than on the MGMAT CAT exams.

Additional Information - Test Scores
My practice test scores ranged from 640 when I first started to two peak scores of 750 and 760 approximately a week before the exam. I think scored in the 720 range a bunch a few days before the actual exam.

11/05/09 - 640 (Q43, V35) - MGMAT CAT1
11/23/09 - 660 (Q45, V35) - MGMAT CAT2
12/12/09 - 710 (Q47, V40) - MGMAT CAT3
12/18/09 - 750 (Q48, V44) - MGMAT CAT4
12/23/09 - 760 (Q49, V44) - GPrep1
12/26/09 - 720 (Q44, V44) - MGMAT CAT5 - Finished with 17 minutes left on Quant
12/27/09 - 000 (Q47, V00) - MGMAT CAT6 - Only did Quant Section
12/28/09 - 720 (Q47, V42) - GPrep2*

12/29/09 - 720 (Q47, V42) - Actual GMAT Exam

*I started trying to adjust my sleep schedule in the last week so that I wouldn't be super tired during the exam. I was going to sleep very late (basically in the morning) and waking up late during the past 2 months that I was studying - I feel like that might have affected my score a little bit also? I'm hoping the 750 and 760 aren't just fluke scores and can achieve higher than a 720!*

Other Factors:
1. I feel like I've spent a large amount of time studying for the GMATs. Is it worth it to invest more time?
2. My business school package is relatively normal - doesn't stand out. I was hoping to get a high GMAT score to help differentiate myself.
3. How much more improvement can I expect?
4. I can either take the exam again in about 1 month to hopefully get a better score consideration in for this years B-school apps, or wait basically another year till next years apps.

Thanks to anyone who even read this entire post. I know it is very long. Also, thanks in advance for any advice anyone has for me!