I've spent many years collecting my favourite Arcade games and just have to mention and share the joy of MAME!
The Multiple Arcade Machine Emulator is one of the best pieces of FREE software you could ever own if you still own a PC or laptop. The old Jama PCB's were converted into binary ROM zip files that can be loaded into MAME and the application serves as a complete solution for all the games you played as a chid. Simple is always better and although the graphics are only 8 bit, it's plenty of fun and the games don't last hours as you're always getting killed :)
Check out Internet Arcade to play these games online. I did put some Roms up for download a while back but my server bandwidth got cained so i had to limit the downloading to registered users. Use Mame Arcade Rom Download to access the Roms section if registered.
I've yet to build a dedicated Arcade Machine for myself as space does not permit, but it will happen at some point as there's nothing like a bit of button bashing arcade classics.
All the Arcade classics of the 80's and 90's..