I have seen a range of comments here from people with an Athlon 64 processor but only having Windows XP Home installed.
First some bad news, Microsoft has EOLed XP Home, they recoment moving to XP Pro or XP Pro x64.
x64 was RTM back in Mar 31, 05 so its not quite a year old in the market place, so its not going to be as rich for drivers.
I have an Audigy 2 card, drivers for x64 are available, I have a Webcam Live Ultra, drivers are late, Everything else is OK
Microsoft's Intelipoint and Intelikey dont work. etc. Games works OK, so moving to x64 is relatively painless for a consumer, but bear in mind, XP x64 is not being promoted as suitable for consumers yet. Its more for developers, no media center etc.

XP Home vs XP x64
Christopher
A 64bit cpu isnt even expensive anymore, unless you want a VERY cheap machine. In that case the user wouldnt see the difference really.
Anand Nathan
I had an Athlon 64 since it fist came out a few years ago and I used the beta versions of Win x64 and now use the RTM that i bought the day it was available.
I use x64 myself but my notebook uses XP home which is fine for what I bought it for.
These days, I do web development in JavaScript, Visual Basic (server side) and sometime look at other programming tools that have been ported to the ASP.NET platform. JavaScript is the defacto language for client-side web projects, and VB is the defacto language for ASP and ASP.NET server-side programming.
Virtually every book I have seen in JavaScript (JScript for Microsoft's flavor) and I have been dismayed by the poor quality of books, in part due to the netscape team that developed the language did not document it all that well leading to a lot of confusion. My own site's JavaScript is labeled internally as JavaSciptish as using some of the reserved words in every browser are not supported properly.
I use x64 because I have some programs that exceed the limits of 32-bit computing. while its true that a 32-bit machine can do a lot of useful work, scientific and engineering problems today are so complex with modelling etc that unitil the rise of the x64 based PC I was using a Unix workstation that cost a lot coin.
Consider a CAD drawing of an condominium project that needs to be lofted into a 3D perspective. Such a complicated project may have 30-100 floors that have to be rendered, and such a complicated mesh will not fit in a 32-bit machine.
Games are at the limit of 32-bit computing as well. New technology is needed to deal with the massive amount of computations needed for physics computations to make something like an explosion to look more realistic.
I expect as Intel and AMD both now offer x64 bit processors, I can see the 32-bit PC finally come to a close. Now don't think that 64-bits is any panacea. I have every reason to expect 128-bit processors will begin to surface in 5-10 years from now. The reason is network file systems (NFS) are growing as disks get bigger and bigger and kludging is a big performance hit.
ljdev
Many people out there probably don't need or want to switch from Windows XP Home Edition to Professional Edition. Right now XP Home costs less and comes pre-installed on a lot of computers. For some people, XP Home is easier to use with features like the simple log-in screen as default and easier-to-use Windows configuration. And, on the flipside, XP Professional has features that the home user may not need or even understand how to use. And, also, they don't really need the added features most of the time.
There are cases where XP Professional is a better choice. Professional has more features for networking and administration, and some people and businesses can benefit from that. People with more than one CPU can benefit from XP Professional, which can support two processors simultaneously. XP Professional also includes Automated System Recovery, support for sending and receiving faxes, File Encryption and access restriction. Personally, I use XP Professional on one of my computers and XP Home on the other. For me the XP Home is fine for home use, it contains the features that I need.
If they have a qualifying 64-bit processor they should really consider using XP Professional x64. That would be the best way to get the most out of their computer.
Renze
Here’s the URL for the 64-bit Intellitype:
http://www.microsoft.com/downloads/details.aspx FamilyID=18cb8e7f-ecd3-424d-870c-32288020f788&DisplayLang=en
and the 64-bit IntelliPoint:
http://www.microsoft.com/downloads/details.aspx FamilyID=d7e1d03b-3fbd-44f3-a7bf-e84df41a6932&DisplayLang=en
I hope this helps.
Lee Hart [MSFT]
This posting is provided "AS IS" with no warranties, and confers no rights
Karen Chen
We are seeing the limitations of 32-bit systems. As you mentioned, games are starting to require the most you can get out of a 32-bit system. Not to mention all of the other programs that require great amounts of system recources.
If you look around the main site you can see that they plan to include the Media Center in at least one version of Windows Vista.
I don't think that Microsoft and other software companies should stop supporting 32-bit yet, but I am ready to make the move from XP 64-bit to a Vista 64-bit system as soon as it comes out. Who knows, I might just build a new computer for it.
TommyJ
northern
I am hoping Vista will be able to bring more to 64-bit computing. The limitations of 32-bit systems is starting to surface here and there. Lucky me, I have a KVM switch.
I have 2 towers and a notebook. The notebook came with XP Home, the old tower has Media Center 2005 (XP Pro, and its cheaper too) and its use mostly as a TV set (and tunes). The newer tower has XP Pro x64 on it and use it for programming mostly. Games mostly work on it too. Drivers are quickly maturing, making x64 a great choice for gaming now.
My Canon MP780 handles the fax etc. I got drivers for all versions of Windows.
Vista will be behind while drivers catch up. I have heard though that intrinsic drivers in the current Dec beta 2 are abundant, needed to get the OS off the ground quickly once its in the channel.
Some games already want 2GB of RAM (Battlefield 2) which is all Win32 can see. 64-bit Windows can see lots more, making it suitable for more advanced games going forward.
If Media Center can make it to Vista 64, then there is no more reason for 32-bits left in my opinion. Then I can chuck the old tower at last.
Interesting is the new WinFX SDK that extends the Vista desktop programming environment to Wndows XP. It might buy more life for older machines as projects can run on anything from XP Home to Vista-64 and all look the same. Combined with the .NET Framework 2, its enough to keep me busy for a bit.