Windows – but Which? (What to install on Mac Pro Quad Core?)

Question

First, apologies in advance if this seems like repetition of a recent topic, but I read through the recent "Vista vs XP" thread and it didn't quite answer my questions.
Basically, I'm planning on buying a Mac Pro "Quad Core" 2.8 and installing Boot Camp and a Windows OS startup. This puts me into the notoriously tricky area of picking the right version of Windows for my needs, something I haven't really had to deal with in regards to OS X.
Basically, I'm not looking for something with too many bells and whistles or to much bloatware built into the OS. Also, I'll probably be using some older software/shareware, so backwards compatibility is an issue. On the other hand, I'd like something that works with the Quad Core architecture at its greatest efficiency.
This means I'm wondering about a couple of features that I may or may not need, and it would be of great help if you folks could point me in the right direction regarding these:
x64 – Since the Xeon processors in the Mac Pro are 64-bit processors, am I better off with "x64"-compatible versions of Windows (either Windows Vista or x64 versions of XP)? Will this cause problems starting up older programs that may not have been written for x64?
*Dual Processor Support* – the Quad Core, of course, is a dual processor – will I get better performance from a version of Windows that list "Dual Processor Support" among its features (basically, the "pro", "business", or "ultimate" versions of XP and Vista)?
If I need those features, I'm probably looking at getting either the x64 version of Windows XP Pro or the Business or Ultimate versions of Vista. However, I'm leaning against Vista based on backwards-compatibility and bloatware issues. That leaves XP Pro x64, but I might go for a more basic version of XP if I find out the x64 or DPS features aren't actually something I need. (The other "extras" in XP Pro don't sound like anything I need.)
Also, I'm likely to install Parallel Desktop at some point and don't want a version of Windows that would have compatibility problems there, either.
Anyway, any answers you folks can provide for me in this regard would be very helpful.
Thanks in advance,
Peter

Answer 1

Truth is, I am disappointed in VMware Fusions slow walk toward full support for 64-bit and SP1 but 2.0 beta is getting there. Never used Parallels but best to check their own support forums. They also updated the 1.x version recently.
http://communities.vmware.com/community/beta/fusion
http://forums.parallels.com/
You don't need anything first, except I would start with a new hard drive for Vista, don't even do anything with it and pull OS X drive, boot Vista DVD and go from there, just as you would normally. Much easier. After it is installed is when you need Apple BootCamp from your Leopard OEM DVD, install, and then Apple Software Update will take care of 2.1. And install your graphic drivers yourself.
The problem(s) come with trying to use BootCamp Assist and setting up partitioning, and it only makes it harder - not easier - on Mac Pro (you aren't and don't want to use your OS X boot drive).
Windows on Mac forum @ MacRumors
http://forums.macrumors.com/forumdisplay.php?f=86
And their Mac Pro area http://forums.macrumors.com which has a lot of Vista talk from Mac Pro owners.
The only real issues are which graphics card to get today or in next weeks, what drives you are going with and other upgrades like memory (8 x 1GB is actually a good base ideal figure so all DIMM slots are taken up).
Barefeats has a number of benchmark articles:
Radeon 3870: http://www.hardmac.com/news/2008-06-16/#8451
Vista graphics: http://www.barefeats.com/harper11.html
Memory: http://www.barefeats.com/harper12.html
Drives: http://www.barefeats.com/harper9.html
WD 300GB Raptor: http://www.barefeats.com/hard103.html
- this is the drive to die for, but not natively supported
I buy most of the upgrades I need over the last ten years from OWC http://www.MacSales.com that specializes in Mac.
http://eshop.macsales.com/shop/memory/Mac-Pro-Memory
http://eshop.macsales.com/item/Western%20Digital/WD6400AAKS/
- until the WD "Black" series (I guess Blackbird name or SR71 are already taken) along with 3rd generation of their RE series drives. WD has been popular, reliable, with Mac Pro for last two years. Can't say the same of every vendor. Samsung F1 is also a real winner.
If you buy only one book to understand and get the most out of OS X: "Mac OS X: The Missing Manual" (Pogue has a Missing Manual Series on most everything, and this is the most popular recommended for Mac OS).
http://books.slashdot.org/books/08/02/27/1551206.shtml
I needed 3-4 for Vista before I found "Administrator's Pocket Consultant" and O'Reilly's "Vista Annoyances" are both excellent along with MS Press's "Inside Out."