My experience:

 

XP was the most stable (or predictable) of all for me if I followed one rule: only one flight load per FSX start, which was annoying. Otherwise it would crash 90% of times for memory reasons.

 

Windows 7 64: Had some issues with menus and minimizing and sometimes flight would not load I don't know why, but it was rare.

 

Windows 8 64: FSX and NGX actually work better than on 7 for me, but other addons became annoying. Active Sky rarely crashed on 7, but started crashing frequently on 8, although I think part of it is related to SP2. And the joystick stops working if I don't use it for some time, which is the worst issue of all. Some people managed to fix it, but I couldn't.

 

I would go with 7 x64

I have been on Win7x64 since the day it came out.

 

It is the best OS yet- and after some experience with Win8 on a laptop and WinServer2012 (win8 for servers) I think that MS's latest OS is a joke that cannot be taken seriously...

 

Your mileage may vary. 

Why not install both operating systems. I've got a laptop running Win 7 professional 64 bit on the main C drive and Win XP SP3 on a separate partition. Gaming seems  better with Win 7, while some office programs better on XP as do video editing software/capture programs.

 

I can't imagine video capture and stuff like that working better on XP - XP can't address most of the RAM in a modern system and RAM is crucial for those kinds of tasks.  I haven't touched XP in many many years and I'm positive I never will again.

I have been on Win7x64 since the day it came out.

 

It is the best OS yet- and after some experience with Win8 on a laptop and WinServer2012 (win8 for servers) I think that MS's latest OS is a joke that cannot be taken seriously...

 

Your mileage may vary. 

Lol, this reminds me of this:

 

Windows 7 64-bit is the best OS Microsoft has ever made, bar none. Stay away from 8.

 

+++++ from me on that!

 

Don't see that Windows 8 is bad other than that the interface drives me crazy.  Only have it on the wife's new laptop and I stay away from it until she needs help with something.  Then I get frustrated just remembering how to do what should be simple things, like finding and opening Control Panel.

 

I believe from what you said that you are building a new system and the OS you choose will be a fresh install to a new hard disk.  That is the time to migrate.  I learned many years ago that upgrading from a previous Windows version on an existing system is not the way to go!

I can't imagine video capture and stuff like that working better on XP - XP can't address most of the RAM in a modern system and RAM is crucial for those kinds of tasks.  I haven't touched XP in many many years and I'm positive I never will again.

 

I guess that depends on what video editing software your using, I've found Cyberlink Powerdirector works much better under XP, it keeps crashing with Win7

I do a fair bit of

 and find Windows 7 is great.

 

Basic method is "If it's not running in Admin mode, it's not running properly". Run everything in Admin mode.