I play pacman all the time. It is one of the best games ever and is just brilliantly epic.Great for wasting 5 minutes ot 5 hours. Frogger is cool to and so is pong. I still play Doom all the time as well.
I love classic games... but primarily by 'classic' I mean 'NES/SNES era' games. The re-releases and compilations in recent years like Sonic Mega Collection and Mega Man Anniversary Collection, re-releases of the earlier Final Fantasy games, etc. etc. make me happy, as well as actual NEW ENTRIES in 'classic' series like Mega Man 9 and Gradius ReBirth.. and then.. of course you have tons of indie games like Cave Story, La-Mulana, and all that which have that distinctive style.. as well as of course Flash games in the same vein.
I always loved that tanks game on SEGA when I was a kid. Everyone who had that console had tanks. It was the best multiplayer game on old 16/32 bit consoles.
If you like old games there is one angry fellow on youtube who is reviewing the. Really angry dude : )