Old Consoles' Controllers to PC

[Samnitmar]

Hey, I'm planning on making a MAME cabinet, and my dad had the idea of hooking up controllers from N64, Genesis, PSX, ect. to the PC in the cabinet for a better feel when emulating those games. I'm wondering where to get these controllers for cheap, and devices to hook them up to the PC.
I'm also wondering what kind of PC I should get for the cabinet, and what I need for the control panel (Buttons, joysitcks, encoder-thing, ect). Thanks for helping out!

 

[FAST6191]

N64 and PS1/2 fall into USB adapter territory. The xbox 1 is USB by any other name, the new consoles are also fairly common standards.
Earlier consoles do have some adapters:
http://www.retrousb.com/index.php?categoryID=79

Genesis/megadrive used D-sub connectors but bear no resemblance to standard "serial" ports. Still:
http://pinouts.ru/Game/genesiscontroller_pinout.shtml
and a few more:
http://pinouts.ru/pin_Game.shtml

As for controllers I find dead ones a nice source of controllers as most merely have broken leads or bad switches (trivial to replace but then I do such things every day).

As for what kind of PC, the PS1 has been emulated very well for years and can work on sub 1GHz single core with a few filters thrown in for good measure. The N64 on the other hand along with some of the more high end (read recent) systems MAME supports can and will take as much power as you are willing to give, you could do basic N64 on similar to specs for the PS1 (the xbox has a half decent emulator as does the PSP) but do not expect much.