Hi Hughes, just a few I thought you might like though some are pretty hard to find.
Thom Yorke - The Eraser (you've mentioned Radiohead so you'll love this too)
Slint - Spiderland (Can be hard to find but you won't be disappointed)
Low - Trust (Try anything by Low, pretty diverse across the board)
Azure Ray - Azure Ray (bitter sweet, beautiful voice)
Ludovico Einaudi - I Giorni ( lovely solo piano)
Max Richter - The Blue Notebooks / Memoryhouse (Classical with a whiff of WW2 and Kafka / Beautiful)
Stateless - Stateless (Fairly similar to Radiohead, DJ Shadow raves about it)
Port Royal - Flares (underwater tingly)
Eluvium - An Accidental memory in the case of death (grandiose downbeat music)
Fink - Distance and Time (superb acoustic pieces)
Aereogramme - My heart has a wish that you would not go (scottish heart rendering stuff)
Halves - Haunt me when I'm drowsy (only just got this, similar to Sigur Ros, really good)
Mercury Rev - Alll is dream (oldy but goody)
Galaxie 500 - On Fire (Pearl jam era but more mellow)
Archive - Lights (Indie trippy hoppy deep stuff)