Hundreds? I'd say thousands, but I think even I'd underestimate ME2's fans.
As for getting hooked up on games, the same went for me and MW2, one night and it was all over. But it's gameplay was fast paced, dynamic and very exciting however ME2's gameplay takes the prize. ME3 couldn't come soon enough. Getting down with the ME2 sickness
alcatraz is right. its one of the best games i've played in a loooooog time. it makes me keep coming back for more. i've already played it twice..playing it the third time. it even made me bring out ME1 from cold storage so that i could use its save game. u should get it as soon as possible.
Id def finish it, most of your choices in ME1 make a huge difference in ME2. to me its really cool how all your evil or good deeds from the first, change so many "lives" in the second. Prob the same way in number three.
i myself am a perm fan, im picking up the comic series (that fills in the two year gap between 1 and 2) then a few of the audio books etc. Fan boy or not i really like the series.