Sam & Max wallpaper

Well, actually Max only, but still... Get it.

Planescape Torment Wallpapers

Six excellent wallpapers from one of the best RPGs ever released can be found here (after you scroll down a bit). Available in every resolution between 640x480 to 1280x1024.

Mario Kart Wallpapers

If you still haven't given up on your plastic wheel, well these might just be the desktops for you.

The Complete (?) Lynx Wallpapers

Just ignore the odd post title and follow this excellent link to some of the best wallpapers ever created. They all are about the Atari Lynx of course, the first and best (well, almost) colour handheld console ever, and cover everything from the hardware itself to its classic games. Oh, yes, you'll also find some rather great Atari Jaguar desktop images too.

Rez (and Rez HD) Wallpapers

Rez on the Dreamcast was beautiful, innovative and relaxing. Rez HD was a great update and now you finally get all trippy with your desktop. Rez wallpapers here, here and here.

ZX Spectrum Desktop

Just grab it.

Atari 7800 Wallpaper

The console that almost saved Atari has a fantastic mid-80s styled wallpaper to grace your desktop. Get it.

The Walking Dead Wallpaper

Not game related, but absolutely brilliant. Grab it here.