killer b said:
you should get the sunn O))) / boris album (altar). it's fucking AMAZING.
seconded.
rosy parlane - 'jessamine' cd is superb.
growing, esp 'his return', 'the sky's run into the sea' and a split cd they did with mark evan burden. the burden track is boring imo, but the growing one is very powerful, really portentous. (growing's non-drone stuff can be really beautiful but very stop-start, which i can find wearying at times.)
boris - flood.
white/light (due to the name it would probably help to search with the record label details - rebis records). sunn O))) meets kraut rock with some power electronics style stuff, but with a spiritual slant.
white lichens - white/light collaboration with lichens, very atmospheric, blazing guitars/fx, inspired by spirits of the goetia. (lichens well worth checking btw but not always that droney, just deeply mystical. their 'omns' cd contains some of the eeriest music i've ever heard.)
organum - amen (actually loads of their stuff is excellent but tends to be out of print and collectible and therefore dear. also very obscure so i don't know how often it turns up on slsk etc.)
phill niblock, esp the triple cd on touch called 'touch three'.
rst - axes. isolated, crystalline guitar-based drone.
hth