I bought a Mac for other things, but I use Windows 7 pro on my Macbook Pro and it is great.

I remember when having a Gig of ram was nirvana. Then two became the sweet spot. Now I run 4.

A couple things to remember when upgrading:

Since you're running a brand new computer, highly consider getting the 64bit version of Windows 7. 64bit is the next step in high memory management computing and it's unfortunate Microsoft is still keeping a 32bit verison of windows.

Performance is the biggest reason why you should go 64bit. Also consider with ultimate you can also run 32bit XP mode, which saved me since Texas Instruments didn't take the time to update their calculators and software.

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-Typos courtesy of my mobile phone.