I'm currently saving up for a new computer I'm going to be building, but the enormous Windows price tag (200€ and up) is putting a bit of a dent in my schedule. So I was thinking about going Linux for a while first, and then getting around to Windozing it once I can afford. But pretty much all dual booting guides I can find recommend installing Windows before Linux, so... Would this be a silly idea? Assuming I had just the one disk, would I have to format and start over with Windows and then Linux?
I would recommend the "format and start over" if you decide to make the switch. Whatever you do, you are going to want to backup all your data at that time in case the install doesn't work and you need to restore your system. So no, i don't think it's a silly idea at all, but I also don't see the problem with starting over with Windows first.
What are you using the computer for? Depending on your needs, you may find that you don't need Windows. Most Windows tasks you can do either using Linux or software in the cloud.
I'll be using it for a variety of things, but gaming is going to be a large part of it. So Windows is pretty mandatory in the long run (unless they finish that Linux version of Steam in record time and convert a million games along with it).
In the short run I'll keep using my old computer for gaming, but I thought I might as well get my new computer running and put it through its paces in the meantime. And maybe start getting used to Linux (or at least the distro I pick).
I guess I can just format and start over once I buy Windows. It just seems like an annoying chore to have to start over like that.
The primary problem you would have is that Windows will just wipe out the Linux bootloader without even asking, so you will need some kind of means of getting the Linux bootloader back.
Most distributions should make this possible by running a kind of recovery mode from the installer. All you need to do is make sure GRUB, or whatever other bootloader may be used, is reinstalled and picks up on the /boot section of your Linux drive where the kernel is located, and also the Windows install.
Once you narrow things down to a specific distribution it might be worth posting your question on their particular forums to get a little less generic advice. Just ask about how one would go about restoring a Linux bootloader and configure it for a dual boot as if this were a brand new install of the distribution, but obviously all you want to do is install and configure the bootloader.