qualities of reverb

["Michael Peters" <mp@mpeters.de>]

sometimes I love to listen to the dreamy music of Harold Budd, or Robin
Guthrie (Cocteau Twins). Their pianos and guitars are often drenched in a
very long and dense reverb that would put the Taj Mahal to shame - this
reverb has a depth, richness, and aliveness that is lovely to listen to, it
is not the linear, cold, and boring reverb that comes out of my Nanoverb.
How do they achieve that? it often doesn't sound as if they would simply 
use
echo or chorus to fatten the sound, it often seems to be nothing but 
reverb.
Is it just a matter of using one expensive reverb unit? Are there reverb
units which can create such a sound out of the box?

I've put a Robin Guthrie sample here as an example:
http://www.veloopity.de/temp/guthrie.mp3

Michael www.michaelpeters.de