which console did N64 users move onto?

[Soundwave]

XBox seems to be where a chunk of them went, at least the FPS shooter crowd that really liked the system.

Though to be honest most N64 owners I knew growing up also eventually caved and bought a Playstation, but the N64 was kept around for Mario 64/Zelda 64 and of course GoldenEye all-nighters.