It is McGwire. And you, sir, are on a high horse. Unless I am severely mistaken, you were not actively watching baseball in 1930 either. Hack's 191 RBI season is one of the greats in baseball history.
But it had nowhere near the drama or national attention of the 1998 HR chase. Subsequent events notwithstanding.
Maris' 61 in '61. Ripken's streak. Gehrig's retirement. The '98 HR chase. Gibson's 1.12. The Shot Heard Round the World. Moments that captured the attention of the entire country, not just baseball fans.