Highly Recommended CHILL OUT CDs???

I had not heard, nor hear of BLISS before your post, but after a quick listen, (I really like it) here's some I have that are similar:

Global Communication - "76.14" (this is very similar to "Quiet Letters")
The Future Sound of London - "Lifeforms" (Also similar)
Brian Eno - "Drawn From Life", and "Apollo: Atmospheres and Soundtracks", most of Eno's other "ambient" releases
Harold Budd - "Avalon Sutra" (less similar, but still ambient)

There are lot's more I have, but those are the first that come to mind.

"Electronic Realizations for Rock Orchestra" - Synergy

good call . . . Larry Fast (aka Synergy) recorded multiple albums and they are all great, though a little higher energy than the reference recording.

Here's a new one:

Klaus Schulze and Lisa Gerrard - "Farscape"
It's a new release (August 2008) 2 disc CD and amazing. I just got mine yesterday and have only had a chance to listen to disc I, but it alone is worth the $14.99 I paid. It has those great Lisa Gerrard chants, Klaus's usual synth work with some great deep bass synth notes.

Also, good call by Branislav - Mike Oldfield "Song of a Distant Earth"