The 64-bit install is about 10 GB out of the box, with 32-bit being probably a couple of gigs smaller. This will grow over time due to things like winsxs compatibility files, however. The very generous space requirements Microsoft has quoted are to factor in the swap file, hibernation, winsxs, patches, etc. to give the OS some room to breathe.
XP Mode is not counted; it will need several gigabytes more. The virtual hard drive space allocated to XP Mode does not actually take up any space until it has actually been used within the VM, so the more you install in the VM the bigger the VHD will get. You can put the image on any partition of your choice or even move it later on, so that shouldn't be too much of a problem.

I never did bother installing the beta version. And I'm not sure I can be bothered to dig out another hard drive to put Win 7 on right now. And I certainly don't want to do anything that will mess up my XP install. I managed to do that once already when trying to create a dual boot system a few years ago >_<.

You'll probably upgrade to Windows 7 when it goes gold, right?

That depends on how much Microsoft charge for it and how easy it is for me to get it in English. The main reason I never moved over to Vista is that it was nigh on impossible to get it in English and the Japanese version is still priced at over 18,000 yen for an upgrade to Home basic and further 25,000 to subsequently upgrade that to Ultimate. Way too much.

Download that one here: http://www.microsoft.com/windows/virtual-pc/download.aspx

Thanks, I'll be checking it out later this week, I got a lot of work to do with my band over the next few weeks.

Win7 seems to scale down much better than Vista does, according to what I've read elsewhere, it should work reasonably well.

I've been using it as my primary OS for approximately the last week. It's been pretty stable, there are a few issues that I've encountered but nothing that I couldn't get around or were merely aesthetic in nature. I've found it to be incredibly fast and much less of a resource beast than Vista. It still needs a little bug fixing here and there, but overall it's a much improved version over Vista, and an improvement over the previous public beta build.
As for the XP mode... meh, I use VPC anyway so it's of little consequence to me. Although I do enjoy the look of the integrated desktop.

Needs 3 GB moar amirite

My Win XP install (OS only) still fits in a measly 2.5 GB, even with all the updates and service packs. That leaves the rest of my two 120GB hard drives for anything else I want to use on my PC. Frankly, that's what an OS should be, just what you need to run the applications you want. Even if I had terabytes of storage space, I still wouldn't want the OS to take as much as 20 GB of space. Win 7's size is just another indication of how badly bloated Windows has become.

Never said that I wanted or feel its necessary for an OS to be 20 gig or so, just stated that overall nowadays ( if you're not on a real budget ) then 20GB isn't much. Heck, just installing a game can run to almost half that size.
At any rate, my win7 install ( fresh, with just a few minor updates and just counting the Windows directory ) is at 11,4GB. This does not include the WinXP VPC which I've installed on a different partition.
Interesting to note that the damn winsxs directory in there takes up around 5.5GB of that space in total which seems excessive for a nearly fresh install and based on what the directory is for - link explaining
That still leaves around 6GB for the rest ( and another 1.2GB in the User directoy )

If it was Vista, I would recommend 2 GB at least (that's what I have, but with what I run I'd like 4 or 8), but Windows 7 (as I said earlier) seems to scale back much better that Vista does, 1 GB should be plenty (obviously depending on what else is running except the OS), it shouldn't require much more than a fully updated XP does with similar software running.

Yeah, and my Mac OS 8.1 fits in a few dozen mega bytes, DOS with Windows 3.1 likewise, your point is? Programmers code software that does more, looks fancier, and is less optimised when they (and the general public) get the hardware resources to do so, system requirements go up, regarding all of processing power, working memory and long-term storage.

The bloat with windows comes from giving you absolutely everything in large packages. A mate of mine was tooling around with xp a while back and managed to get the install down to something like 230mb by stripping out everything that wasn't essential. He pulled out old drivers, programs and even pulled the system critical DLLs apart and removed pointless icons he was never going to use
What I'd like to see is an old school minimum/default/maximum install option. The maximum does absolutely everything & to hell with the drivespace, the default would be a balance and minimal would install no drivers other than those for items connected at install, install no sample videos, no annoying windows sounds or games and none of the flashy "hey you've just installed windows!!" intros. Basically a shit-free install for the people who've had the 'xtreme xperiece' before and just want to install a basic OS.
Couldn't you just order it from Australia or somewhere that would have english as the default? Can you at least get it in Engrish? That'd be worth it just for a laugh

Not that I've found. Such as for Amazon, they carry this wonderful text:
Shipping: Currently, item can be shipped only within the U.S.
Which is why I say it's pretty much impossible to get it, as no one appears to be importing (probably because M$ don't want them to).