Demonoid

You will definitely love Inside then.
Something like Pink Floyd's Piper, mixed with the hard-rock of Uriah Heep and some krautrock influences. Psychedelic, but a lot less commercial as well. It's more hard rocking than, say, ambient.
But the organ is the centre of attraction here.

I would say Ocean is pretty atmospheric as well...although kinda symphonic. The concept and the musicianship are superb.