Is there anything I need to worry about if I want to use a 32 bit version of Windows XP on a 64 bit machine?

yeah lots

No. 64 bit ISA extensions are just that -- extensions. This means that your processor still supports all the old instructions and thus the old OS will run just fine. However you have to consider that you now cannot take advantage of your 64 bit extensions because your OS will not support the software.

-AntonK

I'm doing it right now, and nothing bad is going on.

Most people with modern systems are since they run XP. I am one of them. I only get the advantage of the 64 bit architecture when I switch back my 64 bit Linux side.

-AntonK

I have a legal 64 bit copy of XP that isn't installed. I don't know how reliable it is or anything, so I've never wanted to take the effort of installing it.

my machine supports a 64 bit OS but i am running a 32 bit OS.
i see no problems.

I appreciate the help, people. The issue is that I only have a 32 bit version of XP and that will be the case for some time. One of my options for a better computer is buying a barebones kit and processor. The difference between a 32 bit kit and a 64 bit kit is about 5 dollars American. No point in buying a 32 bit kit, is there?

Is there anything I need to worry about if I want to use a 32 bit version of Windows XP on a 64 bit machine?

No. I have a 64-bit AMD Turion in my laptop and I run 32-bit windows XP.

I went up to the 64-bit version of Windows XP but I got tired of the hell I received from drivers and incompatable programs that I gave up and went back.

I appreciate the help, people. The issue is that I only have a 32 bit version of XP and that will be the case for some time. One of my options for a better computer is buying a barebones kit and processor. The difference between a 32 bit kit and a 64 bit kit is about 5 dollars American. No point in buying a 32 bit kit, is there?

Go ahead and buy the 64-bit processor. You could use it should you choose to uipgrade to Vista (whenever that comes out).

Go ahead and buy the 64-bit processor. You could use it should you choose to uipgrade to Vista (whenever that comes out).
concur.
if the price difference is only 5 bucks then spring for it

No. I have a 64-bit AMD Turion in my laptop and I run 32-bit windows XP.

I went up to the 64-bit version of Windows XP but I got tired of the hell I received from drivers and incompatable programs that I gave up and went back.

Not again. We do not need more ways to go through hell with strange actions, reactions, and non-actions from a new operating system. I have no idea if the 64 bit systems can enhance throughput over a 32 bit system with a 32 bit OS. Some enhancements to architectures are transparent to and independent of operating systems but I don't know much about those.