Lester Flatt and Earl Scruggs? This is bluegrass, a subset of americana. Flatt’s an American legend, a great American songwriter and singer. Scruggs practically invented bluegrass banjo.
Banjo pickers who bring a unique style like Earl Scruggs and Bela Fleck are rare and as such probably can’t be replaced. Earl Scruggs and the Foggy Mountain Boys had far greater effect on bluegrass than Johnny Cash had on Nashville – “playing a lick,” that’s Earl Scruggs – but I really prefer the rawness of Ralph Stanley’s banjo take on Scruggs style banjo playing (woops, Dr Ralph Stanley). Stanley’s forward rolls are nearly unique in their expression of that little break with rationality that precedes ecstasy (in Stanley’s case, it’s religious ecstasy). That little break with rationality is also at the heart of ecstatic American Christianity today. I think it’s also what explains the public behavior of Sinead O’Connor (different flavor of ecstasy, though). Also, Stanley’s clawhammer style is so percussive and just drives the song. For example, Dickson Country Breakdown. Or The Clinch Mountain Backstep. Ralph Stanley can make the hair stand right up on my neck. His music is really spooky in a way that, say, bagpipe music is spooky. A Scots-Irish thing chased out of Pennsylvania and into Appalachia during our Whiskey Rebellion, spiced by the American Civil War and World War I, and that popped up in the hills of Virginia in the first half of the last century.
As the chief said upthread, Austin is the capital of americana music, but an excursion to the hinterlands takes place at the Walnut Valley Festival in Winfield, Kansas, every fall. The national flatpicking competition is held (along with other national americana championships), and guitarists from around the world compete. The competition is way cool. What happens is that there’s a registration, a time and a big tent. If you’re registered, you show up at the tent at the designated time. They call your name, you step up and play your piece, applause, the next artist is up. They just flat get with the program. Intense yet warm, very serious, very competitive, very fair, and a jaw-dropping ninety minutes slides right by. Pretty amazing competition. And the mostly spontaneous, informal playing that runs every night in the campground is of amazingly high quality.
Alison Krauss, Del McCoury, Bela Fleck, Rhonda Vincent, Ricky Skaggs (a great, great mandolinist, guitarist, fiddler, and banjo picker and much underappreciated imo): this is a list off the top of my head of the most successful bluegrass artists today. There are literally thousands of others. Just about every state has one or more americana music festivals, lasting days each. Winfield, Bonnaroo in Manchester, Tennessee, Telluride in Colorado, SXSW and Austin City Limits Festival in Austin, New Orleans Jazz & Heritage Festival in New Orleans, Hardly Strictly Bluegrass in San Francisco: these festivals are where americana music really lives. Doesn’t really thrive on an MP3 or a CD, unfortunately.