OP, You'll continue to get silly answers until you state something about your computing needs. There is no correct answer to your question and it's not even possible to provide helpful answers with the information you've given.
That you're asking this question implies that your current computer is no longer meeting your needs. Is this correct? If so, why?
In all seriousness though, we need more information. If you use your mac for work and want to upgrade, I really see no need to wait unless you are a graphic designer/film editor. The next update should not bring significant improvements in any area other than graphical.
However if you are not a professional I would suggest holding out to see what the next update brings.