Lyric discussion by Murphigius 

Cover art for Nemo lyrics by Nightwish

So nobody thinks it's Little Nemo the Dreammaster? Well, darn. ;p

Seriously, I'd tend to lean towards the Jules Verne idea, from the water imagery in the song - "soothing rain", "sailing home" and "compass" - the choice of words seems to imply the Captain Nemo interpretation. The 'nobody' interpretation works as well, though.

It was probably meant to be both. The more layers the better.