I mentioned some of these songs on another post while back, similar to this one. I just can't think of any other better songs with such astonishing vibes.
Like the ever infamous Moogwai - Viola (Armin Van Buuren Remix)

beyond what words can explain, NOTHING compaires...the best.
CJ Stone - Shining Star (Rising Star Remix) the original is quite good as well. very avant garde too.
Gouryella - Walhalla (Armin Van Buuren Remix) another Armin remix. This guy can take any song it seems, and make it into a true masterpeice.
Thats all I can think of as of right now. In my opinion, these songs are trully "a must" for your music collection.