[sparky_z]

I'm would call that 6/8, no question. It's slow enough that the accompaniment often subdivides into 16ths, giving the immediate impression of each measure divided into two 3/4 bars. But listen to underlying drum beat, and it clearly repeats every 6 beats, so I'm comfortable calling it 6/8.

I might almost call it 6/4, which wouldn't exactly be wrong (as long as you double all your note values when notating). But that's conventionally reserved for unusual beat groupings like 4/4 + 2/4.

[greglindahl]

Waltzes are usually notated in 3/4, and the measures usually come in pairs, which fits nicely with a rotary waltz doing a complete turn in 2 measures.

6/4 is extremely common when notating Renaissance music, btw. Although the originals are often in 6/2. Or lack bar lines, so they're X/2.