To cut a long story short, a friend has got a small arcade with various games... now, here in the office we've got a more-or-less functional 486 DX4/80 which the boss has agreed to donate for that arcade.

What games would you suggest to set up on that computer?
Note: the kids don't pay anything for playing on those machines - apparently, the buiness is partially being funded by some donations from the city and partially by income from selling snacks and soft drinks to the visitors. ^_^

Cyberdogs 1&2 and Liero

Keyboard, joystick or gamepad?

Tyrian is a good one. There are a few good pinball games.

Joe and Mac is a lot of fun and so is Cool Spot. Cool Spot might help them sell soft drinks. :)

i'd say test the waters with cps1 and older games first. that way you have a solid idea of what works before you go onto testing the cps2/neogeo games on there.
a couple of cps1 games to try first:
Final Fight
Megaman: The Power Battle.
if you want to try cps2 games go for:
Marvel Super Heroes
Street Fighter Alpha 3
Super Puzzle Fighter 2
NeoGeo:
Metal Slug: Super Vehicle 001
Shock Troopers 2
Garou: Mark of the wolves.

this is from my experience of testing so i know what my computer is capable of.

Keyboard. Joystick is an option.

"Street Hoop"
"Metal Slug" - everything that you can find
"Cadilacs & Dinosaurs"
"Final Fight"
"Shadow Dancer"

you will not be dissapointed of these games

Try X-Men: Children of the Atom, and Marvel vs. Capcom, or even Dungeons & Dragons: Tower of Doom.

Alien vs Predator (really similar to Cadillac & Dinosaurs)
Metal Slug
Dungeoun & Dragons
Mortal Kombat II

PAC MAN! :ok:

i'd recommend against any of the metal slugs after 2 since they are 60-80mb big plus their a little harder on your system than the first 2. and MKII for the same reason. the main concern with some of the suggested roms is the filesize since i don't know how much HD space this old machine has. for example my roms folder is about 1.34GB.
just a little snippet of my rom folder:
just a word of warning

For some reason, you think this machine is going to run MAME or some other console emulator.

Nope. Just good old PC games for it. :P