Well, I know Bijou had (at least HAD) a HUGE number of people, given that the christmas event crashed my computer every time I tried to log on. And although a lot of the memory was used, it wasn't a bad computer (not as good as mine now tho
)
And Epith is pretty well populated. I dunno how full it is in comparison to Bijou, but it's good sized, at least.
Teva is totally deserted. I'm sorry, but it's true. And Apoline is almost deserted. Almost.
But Bijou is the most, for sure.