Shit, I have spent so many hours of my life playing video games...that shit is unbelievable. Lately I been fuckin around at work just playing RPGs all day and not getting shit done. Anyways, here is a list.
Sega:
Shadowrun <- HELLA hours into that game
PS1:
Final Fantasy <- I would come to school tired as fuck cause I would be up all night playin that shit.
But nothing compares to Counter Strike.
When I first got it I was hooked, at least 4 hours a day for the first few months...then I got good, got into clans and competitve play. I ended up being sponsored and flown to the CPL, etc. That shit was probably 85% of my free time.
I must have 10,000 hours logged playing cs.
Honorable Mentions:
Arena
Daggerfall <- had the strategy guide. Did it all.