Number 1 : Warcraft 3.. not 100 hours, probably 6000 hours
nothing else compares
For other games. The first couple of tekken games.. Especially tekken 3 and tekken tag tournament.
Also lots of the pokemon games on emulator some years back were huge time sinks and perhaps starcraft 2 though lately i couldn't care less about sc2.
The game i'm currently approaching 100+ hours is hearthstone