You can buy Windows 7 online from Microsoft, and they will give you a license key and a download link. You should be able to use that installer directly in Fusion, no need to burn it to a disk.
I would recommend Windows 7 over XP - it will be supported by Microsoft and 3rd party software much longer, and has many technological advantages. You should be made aware that Windows comes in several flavours—in addition to Home Premium, Pro, Ultimate, each of those can be purchased as an Upgrade, Full, or OEM version.
OEM is typically the cheapest, but is intended to be installed once on a computer you build, and can't be reused. Technically it's not meant for VMs, but in practice you shouldn't run into issues with it. However it can only be purchased as a physical copy, not downloaded. You want to stay away from Upgrade versions, which are cheaper than Full versions, but check for an existing Windows install. Finally, Full versions are the most expensive, but if you want to live by the purest letter of the license agreement, this is what you need.
Windows 8 is also an option, and will have cheaper licensing, but won't be available until October.
The Microsoft support page describes the limitations of the 64bit office.
They are the following:
- Solutions using ActiveX controls library, ComCtl controls won’t work.
- Third-party ActiveX controls and add-ins won’t work.
- Visual Basic for Applications (VBA) that contain Declare statements won’t work in the 64-bit version of Office without being updated.
- Compiled Access databases, like .MDE and .ACCDE files, won’t work unless they’re specifically written for the 64-bit version of Office.
- In SharePoint, the list view won’t be available.
- If you have specific add-ins that you use in the 32-bit version of Office, they may not work in 64-bit Office, and vice versa. If you’re concerned, check your current version of Office before installing the new one. Considering testing the add-in with 64-bit Office, or finding out if a 64-bit version of the add-in is available from the developer.
If these limitations do not apply to you (they seem quite advanced and/or obscure to me) then you should choose the 64bit option.
The 32bit version will work as Microsoft is usually quite good in support of older windows versions and architectures, but there is really no benefit to it.
Best Answer
Quicktime is a part of the iTunes install, so if you download the 64 bit version of iTunes, you will get it as a package deal.
You should probably try uninstalling all apple components first if you are getting error codes on installing.
Could you also paste those error codes for further troubleshooting?