i am getting this and i swear to fucking god if this is even half as addictive as Diablo 2 is i will hate you all
I never got very addicted to D2 but this game sucked me in for a while, so I'd say it's probably more addictive. Though it could just be that I really like the mastery thing in Titan Quest more than the classes in D2. I especially like the one in the expansion, I think it's called Dream? Something along those lines.
I've got the discs around somewhere (for both the original and the expansion (can't for the life of me remember what the name of this is)), I think I deleted my characters though so if I were to play with anyone my guy would be level 1.