thinkpad

Most old Thinkpads are really sturdy and reliable and worth getting. I wouldn't recommend getting any devices from the A series, though. All of them have some pretty major flaws. The A22p has a faulty power delivery chip which often fails and makes it not turn on anymore (it will blink green for a second and nothing else, which is also called "Blink of Death"). The A31p has bad cooling on the GPU which makes the GPU die when you're stressing it out too much. The RAM slots also wear out over time and lose contact, so they need to be resoldered.

A series Thinkpads are really cool workstations, but it's also a pain to keep them in good shape.

For retro gaming, I'd recommend the T series (T20, T21, T22). Not the T23, it's a bit too new and has some compatibility problems. The R52 also works really well (and can be modded with a UXGA display from a T43p).

The 770 series is also really good, compatibility-wise, but they have a rubberized surface that tends to turn back into oil, which is really messy to get rid of. I also have a 560X, which is good for DOS and very early Win9x games. The 560X does not have any rubber on it.

Linux does not run well on all of these older devices. They often have S3 Savage and ATI Rage GPU's, which are not supported on modern distributions anymore. Even if you put Linux on it with an old Mesa 7.x driver, their OpenGL drivers are very rudimentary.

For Linux, I'd recommend T400 upwards. The ATI and Intel GPU's in those machines are well supported by Linux.