VHD on both, Main and old desktop, only because I'm too lazy and I don't have free space enough to make a partition

While I reserve seperate system configurations on which to run Windows 8 (seperate from the one where I carry out all of my personal tasks), I voted for "Spare partition", since I still consider all of these configurations to be part of the same system, not to mention that there are other purposes I have for keeping different hardware setups for running my system.

However, I also have a reinstall of Windows 8 running within VMWare Player (formerly VMWare Workstation), since I need a copy of it running within a virtualized environment, for the sake of taking screenshots of areas where the Print Screen key is disabled, or otherwise unusable (for my coming Windows 8 review, that is).

I am using Windows 8 Developer Preview as my main OS. When I get Windows 8 Consumer Preview will do clean installation on it.

If I get it I'll test it in a VM,

Gonna install it over my WDP partition, i may use it as my main OS. I have been using Windows 7 since the beta, it was pretty much stable... windows 8 should be better.

I am currently using Windows 8 Dev Preview as my main, day-to-day OS. Haven't found any unstability issues yet (it does crash once or twice on my notebook though, I reverted to the original Windows XP it came with after the crashing issue). Therefore I'm going to use Windows 8 Customer Preview as my main OS in my PC

As long as your Pentium II system has a fully ACPI 2.0-compliant BIOS, there's no reason it shouldn't run.

Isn't it a bit too early to ask this?

Someone ran Windows Vista on a Pentium at around 133 Mhz if I remember correctly (confirmed by WinHistory.de's page regarding various attempts made at running versions of Windows on lower specifications then they were originally intended to run on), so yes, as linuxlove said above, as long as your system has an ACPI 2.0 compliant BIOS ROM, it should work.

If not, then you might be able to download one from a website and flash it to your system (nearly all systems made within the last fifteen years will no doubt have a Flash ROM), but if even that doesn't work, your best bet would be to find another motherboard that's compatible with your case (most systems have ATX cases, making motherboard replacements easy, that is, as long as you have the knowledge and experience to restore your Windows installation once you're done).

I would possibly test it on my physical machine straight away... But before i will save my data and stuff

Well, I might try it on my PC as the main OS. I'm not using WDP, because the Metro tiles didn't work at 1280x720.

Pop in a spare SSD in the laptop and run it there, or the new VMware should have decent graphics performance.

I'm probably going to run this in VMware if the VMware tools works in order to take it apart look in the registry as well as other pieces of the software there you go. I wish Vmware 8 would work with windows 8 completely so transferring stuff was not a pain in the @$$ since you have to make a ISO each time.

Main OS both on laptop & desktop

VMware Tools works OK in my VM which uses WDP as guest OS, including copying files between host & guest.
When it comes to WCP, it should also work.

Will install Win8 CP on 2nd SSD and dual boot with Win7

I'm going to try this with VMWare too, haven't got a spare computer to install it for test purposes.

Main OS, with sexy dual monitors!

I'm going to use it as my main OS.

I'm going to try it on a spare partition on my lappy. Hopefully I can have some more fun with the metro multitouch, as it made Windows a lot more usable for me.

I testing Windows 8 Developer Preview on my Netbook:

CPU: Intel Atom N550 @ 1,5 GHz
Memory: 1 GB DDR3 Memory
Graphics: Intel GMA 3150

It´s works fine. It´s my main OS.

As much as I would like to test it on a tablet, I'll have to settle for a spare partition on my PC. If it works well I'll use it as my main OS. (just like I did with the Windows 7 beta)

I'm going to run it on my Acer W500 tablet, it already runs WDP just fine as main OS.

Same here
Clean install over the WDP.