*Note* - Versions of Windows XP available to US Market:
Windows XP Home Edition
Windows XP Professional Edition
Windows XP Media Center Edition
Windows XP Tablet PC Edition
Windows XP 64-bit Edition
Windows XP Professional x64 Edition

I am considering building a computer in the near future and using Windows XP as one of my operating systems.

Windows XP Home Edition is obviously the "dwarfed" version of Windows XP.
Windows XP Tablet PC Edition is for tablet PCs.
Windows XP 64-bit Edition and Windows XP Professional x64 Edition are not as stable as the 32-bit editions of Windows XP or their Windows Vista 64-bit and Linux 64-bit counterparts (or so I have read).

That leaves Windows XP Professional Edition and Windows XP MCE2005 Edition.
I have read the wikipedia article:
http://en.wikipedia.org/wiki/Windows_XP_editions

After reading the article I am still baffled by one thing, which version has what?

I know the Professional Edition does not have Media Center installed, and their are third party media center software suites, some of which emulate Microsoft's, so Professional missing Media Center is not a huge deal.

Correct me if I am mistaken, but Windows XP MCE2005 seems like Windows XP Home Edition + Media Center (and a couple things from Professional) but does not contain the full functionality of Professional Edition.

The wikipedia article also boasts Windows XP MCE2005's ability to connect with an XBox 360, but I was under the impression that any version of Windows XP could connect with an XBox 360. Am I mistaken in this?

Ultimately my questions are:
What exactly does Windows MCE2005 Edition contain?
What exactly does Windows MCE2005 Edition not contain?
Can Windows XP Professional connect to an XBox360?

Thank you in advance.

Versions of Windows XP manufactured in the US: none. (XP has gone end of life)

It would seem that MCE 2005 is some kind of hybrid, but there are quite a few Pro features in it. Group Policy Editor also comes with MCE 2005.

You can "connect" to an Xbox 360 with XP Pro or just about any OS, you just can't run it as a Media Extender. Any XP version can enable media sharing with Windows Media Player. That will allow you to play pictures, music, and video from the PC on the Xbox. However, only Windows editions with Media Center will allow the Xbox to run Media Center as an Extender.

Budo, that's good to know. It certainly adds to all of the confusing editions. In addition to all the versions listed above, MCE 2005 comes in 2 flavors: OEM and retail! Who knows how many other of those editions have special flavors. We have MCE 2005 that came with my wife's laptop, so I see lots of Pro features on it.

So, my comments above only apply to XP MCE 2005 OEM flavor.

While using the media center on the X360 would be nice, I assume Vista will do that as well, so I will most likely go with Windows XP Professional.

So are there actual differences in the OEM and Retail versions?

I plan on getting Windows Vista Ultimate when I get Vista. I like to have all the possible features available to me. I understand Microsoft makes different versions as marketing strategies, but I wish they would take a page out of Apple's playbook and only release one version of each OS.

Have a look around the garage sales/car boot sales. You might be able to pick up an old computer for $10 with the original XP installation disk included :)

@jmcguire, the OEM license for Windows means that it can (should?) only be sold to you with a new system or a new motherboard. So, no, you won't have to sell it to yourself. Now, there are some naughty people out there who will sell OEM software without a system or motherboard. You won't find that in any big chain store, but more likely in the little computer shop in a strip mall between a nail salon and a Subway.

@Lighthouse, I don't know how it is in France or the UK, but here in the US anything you buy from the trunk (boot) of a car is very likely to be stolen merchandise. Also, these thieves like to use a van with the sliding side door which allows for the display of more merchandise and a quicker getaway from authorities.

@Budo, I wonder how long supplies of XP will last and is it my imagination, or has the price gone up?

i always look at garage sales for pc's lol :D

The 149 one looks to be multilingual and the 139 looks to be English only.