It really depends on a lot of factors. Are the schools you are targeting reachable with 650? Are you trying to get into a career with a heavy quant background? How much time do you have to invest if you were to make another attempt? Do you feel the Q score really was the maximum score you could have gotten?

V42 is very good as it stands. If you do decide to retake the test and focus on Q while not neglecting your V lessons, you should be able to raise your Q score up considerably. Quant, in my opinion, is easier to improve than verbal, which depends on language fluency (which cannot be improved rapidly in a short amount of time). However, if you feel your Q score is the max then I wouldn't bother retaking it.

thanks a lot mayonnai5e. Iam going to retake the GMAT. Last time I did OG11. Wonder if you can point out some books/references for intense quant prep.

https://del.icio.us/beatthegmat

Check out that link; there are math related links you can visit there. Also, you might want to check out the Kaplan 800 book - it has some good quant materials. I especially like how that book has certain focus topics that it concentrates on instead of going over every possible obscure formula/topic that you could ever need (but very unlikely to see) on the real exam.