... so albums that you could recommend to absolutely anyone with the idea that they would open up new worlds of music to that person

mine would be close between:

1) ulrich schnauss - a strangely isolated place (close enough to the 'ibiza chill' movement that everyone can get it, but opens up an electronic world and gives a glimpse into the world of shoegazing)

2) Sigur Ros - Aegetis Bryjn (close enough) - makes people realise post rock doesn't have to be boring / depressing. Also makes people think glacial landscapes must be amazing and that children in videos doesn't have to be wrong

3) Arcade Fire - Tunnels. No justification needed.

This was hard