Woah, Joe, man, no Cinematic Orchestra at all? Gonna have to remedy that, you know. Here's a very small selection of my favorites, plus their most popular song at the end.
Now, hold for a moment. The next few songs deserve a bit of a special mention. Nickel Creek was one of the bands that first got me interested in music. They were stupendous. Sara Watkins is an excellent fiddler, her brother Shaun's a Mumford-level guitarist, and Chris Thile overshadows them by making almost every other mandolin player in the world look amateur at best in comparison. All that talent alone would make them great - but they worked together almost flawlessly to boot. Unfortunately, they split up several years ago due to internal differences in direction, but the members - especially Chris Thile, and Sara Watkins to some extent - still play individually. Some of their individual stuff is below all the group stuff.
Nickel Creek - When in Rome Nickel Creek - The Fox (live extended version) Nickel Creek - The House of Tom Bombadil Nickel Creek - Toxic - Nickel Creek was quite well known for covering Briney Spears' "Toxic" in live concerts (they never recorded it, since they didn't have IP rights to it). Specifically, they were known for doing Toxic better than Spears, despite the lack of postproduction recording work, despite the fact that they are actually playing instruments at the same time (and well, I might add), and despite the fact that their frontman is, well, a man.
They have far more epic songs than I could list, so if you want more, go find them yourself.:P