Will x86 and x64 on same network cause any issues?

I was hoping that some of the better (than my) minds here could weigh in on something for me.

I'm revamping my folks' computer systems. I purchased three computers for them:

1) Desktop PC: Intel Core 2 Duo E7500 (2.93GHz); 4GB RAM

2) Home Theater PC: Intel Core 2 Duo E7500 (2.93GHz); 2GB RAM

3) Laptop PC: Intel Core 2 Duo T7100 (1.8GHz); 2GB RAM

Should I install Windows 7 x64 on the Desktop PC and x86 on the HTPC and Laptop? Or should I go with x86 on all the machines for consistency? My parents probably will not be expanding these systems ever. They will use the desktop pc for single purpose programs (i.e., burning CDs and DVDs, light Photoshop, etc); the HTPC for blurays, and watching 720p videos; and laptop for email and browsing.

That said, should I just go with x86 on all machines for ease? Is there any particular reason I should go with x64 on the Desktop?

(I might throw 4GB into the HTPC. If I do, and I have two machines with 4GB, should I go with x64 on those two, and x86 on the laptop? Will that cause any issues?)

Any advice would be greatly appreciated.

I have similar laptop. x64 runs fine.

Oh... I forgot...
There shouldn't be any issues.

Sassa said:

I have similar laptop. x64 runs fine.

Ah. Interesting. I never thought about putting x64 on the 2GB machines. Is there any disadvantage in installing x64 on a 2GB machine, particularly where I have x86 at the ready?

If on balance, x86 would work better on the 2GB machine, then, my next question is my first: is there any reason why x86 and x64 would be incompatible on the network?

Sassa said:

Oh... I forgot...
There shouldn't be any issues.

Posted at the same time. Got it. Thank you, Sassa. So, if I have x64 and x86 in hand, I should just go ahead an install x64 on the 2GB laptop too?

Is there any disadvantage or reason not to install x64 on a 2GB machine

I can speak for myself... No disadvantage for me.

If on balance, x86 would work better on the 2GB machine

Again speaking for myself... x64 works better than x86 for me.

is there any reason why x86 and x64 would be incompatible on the network?

No as far as I know.

So, if I have x64 and x86 in hand, I should just go ahead an install x64 on the 2GB laptop too?

As I mentioned...
Speaking for myself... x64 works better than x86 for me.

For the tasks you have described your parents using the computers for, 2 GB of ram should work fine for all of the computers listed with both x86 or x64 versions of windows 7. I would suggest definitely upgrading to 4 GB for power users that multitask or use memory hogs like virtual machines or video editing.

Now days hardware and software companies build x64 and x86 drivers for their products, older products especially printers may only have x86 drivers. X86 would be my bet for the most painless upgrade. If the operating systems are all x86 at this time keep in mind that you can do an upgrade to windows 7 x86 and maintain windows files and profiles while if you are going x86 to x64 you will not be able to do an "upgrade" and will have to do a "clean install". This is a little confusing as you can use the x64 windows 7 upgrade DVD, the installation will just not be able to do a typical upgrade you will chose the clean install option and will loose all windows settings. You can loose files too if you are not careful.