I always feel empathy for people who ask these types of questions, mainly because I've asked them myself and received similar responses.
My sense is the OP would like to know how much better the next MacBook is likely to be than the current model. For example, you can buy the baseline MacBook today with a 1.83GHz processor or the "upgraded" model with a 2.0 GHz processor. For someone not interested in the "SuperDrive," the slight bump in gigahertz may not be worth the extra cash.
Most of you follow the chipsets and have a sense of what's most likely to make its way to the MacBook. So if the OP can choose from 1.83 GHz and 2.0 GHz today, what are the likely choices in June/October? 2.16 GHz and 2.33 GHz? Or could it be worth waiting for: 2.5 GHz and 3.0 GHz?
I think that question is the one that drives these types of questions. Sure, nobody wants buyer's remorse, but they're also looking for an answer more substantive than "If you need it now, buy it now," especially when so many people on this board have real perspective to share.
I think the OP just wants someone to say, here are the most likely scenarios of what could happen in June or October. If that is worth the wait, to you, then wait. If not, buy now and enjoy.
But not a one of us knows
1) when upgrades will come
2) what they will be (chips, configuration etc)
3) what the impact on real world OSX performance will be (as opposed to benchmarks and synthetic tests, or tests on other OS platforms which may or may not have any relevance)
4) what the relative prices will be
5) other than one game title, what the OP is using the putative machine for, and what the performance implications would be for those unknown programs
let alone " Will the new macbooks absolutely BLOW the current models out of the water" - whatever that means to the original poster.
Accept that There are no likely scenarios - especially if you want it pinned down to June or October, there are only wild-@$$ guesses.