Running Windows on a Mac is kind of pointless. Macs are so expensive. You can get away alot cheaper with a PC if you're gonna use Windows anyway.
I'm a little confused, you said you were going to use Logic, why would you even consider Windows then? Logic 7 cannot be run on Windows, it requires Mac OSX.

Hopefully this explains what I meant.I am planning on getting a macbook soon with (Logic).I have been looking thru differant softsynth's recently.Downloading the demos and playing with them in Fruity Loops.I seem to like alot of the synth's that are for PC only (z3ta+ , Sylenth1 ,Zero vector etc).I know you can run Windows on the macbook.Does anyone know how the PC softsynth's react when used on the windows version in the Mac?And what are some good trance softsynths for the mac ?Hope to find help, thanx

The MAC will act just like a PC with Windows installed I believe. So the VSTs will act the same. But again, keep in mind that Logic will NOT run on Windows.

Thank you for your input Eldritch. I know that Logic will not work on Windows.I am just wondering how (if installed) windows softsynths will run on a Macbook.Also could you guys please list some good Trance/Dance soft synths for Mac?

Windows-only VSTi's will NOT run on Mac unless you use Boot Camp, which will let you boot up XP on the Macbook. It really is kind of pointless to do that if your main concern is to use Windows-platform soft synths. Although those are great synths, you still have a whole slew of other choices that are available in AU (Logic's plug-in format) like Rapture (which is z3ta+'s big brother), V-Station, Pro-53, Vanguard/Nexus, Reaktor, etc. There are PC versions of all of those if you want to check out the demo before you get your Macbook. Good luck!