I'm glad you put the dreamcast in there. It INVENTED gaming console usage of internet, and it INVENTED good 3D graphics.
But the PS2 holds many of my past childhood memories, plus it has my four beloved games: .hack//infection, .hack//mutation, .hack//outbreak, and .hack//quarantine.
I'm sorry, but I have to vote for the PS2. It feels so right to me, and sometimes I get really sentimental when playing on it.