Since it’s no longer supported in Blender. Frankly in my experience, Windows after XP has mostly sucked. (IMO at least. Too many things have broken on other computers that shouldn’t have.) So which Linux?
Ubuntu looks ok on the surface, but still seems too bloaty. I prefer a lean and mean desktop to showwy stuff I don’t need. (Not quite pared down to a CLI though, that’s a bit too far.) I’m thinking Mint or Arch, but any other suggestions? Definitely still wanting to keep XP though, as a lot of legacy stuff I still use without problems otherwise. (Printer, camera, graphics software, etc.) Also it should be ok to dual with Linux on 64 and XP on 32, as I’ve got a 64-bit chip, right? Anything else to watch for?
I really like Mint, as everything just works, in my experience. I used Fedora for many years, but it got too bleeding edge for what I wanted to do. It doesn’t matter too much which distro you pick, as you can always put whatever desktop you like on it, and change it anytime as well. Lean and mean can be many different things so I’m not sure what you are looking for. XFCE is considered a fairly lean desktop although there are others that are even leaner (fluxbox, etc?). Other desktops have the minimal look, like Gnome Shell, but I don’t consider it to be lean on resources.
Once you have a distro installed you can play with as many desktops as you like, that’s half the fun.
I wouldn’t recommend Arch as a first distribution unless you’re prepared to learn a lot of techincal aspects of linux right from the start, a better idea would be to install VirtualBox and install a few distributions in virtual machines so you can figure out what you’re comfortable installing and using before you dualboot XP.
And Mint is based on Ubuntu so if you really want to stay away from Ubuntu you might not want to use it.
As for dualbooting XP when you figure out what distribution you want to use, it can either be easy or difficult depending on how your distribution configures the bootloader it installs, or if you have to setup the bootloader manually like with Arch, Ubuntu can automatically resize your primary partition and setup the bootloader automatically for dualbooting.
And don’t forget about Fedora, it’s pretty good from what I’ve heard and a lot of people use it.
Also there shouldn’t be any issues with mixing 32/64bit OS’s.
