Am I the only one who thinks that Jeremy Soule isn't that godly awesome? (Based on his work on Dawn of War and Guild Wars.) I mean, he has done some very nice stuff, but most of his ambiental tracks are... boring? In my opinion, at least.
My favourite is Masashi Hamauzu (SaGa Frontier II, Final Fantasy X, Unlimited SaGa, Dirge of Cerberus, and the upcomming titles Final Fantasy XIII & Sigma Harmonics).
Hamauzu is, in my opinion, a versatile composer that can make awesome ambiental tracks that manage to be as melodic and/ or catchy as Nobuo's tracks, something I don't see composers like Sakimoto and Nakano doing. Plus he is very creative, and doesn't follow the stereotypes of Video Game Music. I mean, look at his "Thunder Plains" track from FFX. He made a happy & relaxing track for a dark, chaotic dungeon, and was able to make it fit perfectly. How many composers can do that? He even admitted that he is looking to revolutionize (spelled?) VG Music, that he doesn't wants to make a Town Track that sounds like a Town Track, or a Dungeon Track that sounds like a Dungeon Track, because he feels any composer can do that. Instead he does stuff like Thunder Plains, among many other examples, that manage to fit the areas perfectly while still giving a completely different mood that one would expect.