The US for me. Why? A ton of my favorite bands from many genres come from here:
-Rock and Alternative: Wilco (favorite band ever), Pixies, Spoon, The Replacements, Modest Mouse, Built to Spill, Pavement, The National, The Black Keys, Nirvana, Tom Petty, The Hold Steady, Vampire Weekend, Smashing Pumpkins, White Stripes, Velvet Underground...
-Punk: Minutemen, Fugazi, Husker Du, Titus Andronicus, Sonic Youth, Bad Religion, No Age, Fucked Up, Surfer Blood...
-Folk and Bluegrass: The Avett Brothers, Bob Dylan, Andrew Bird, Punch Brothers, Bon Iver, Joshua James, Bltizen Trapper, Johnny Cash, The Decemberists, Neutral Milk Hotel, Iron and Wine, Carolina Chocolate Drops...
-Hip Hop and Electronic: LCD Soundsystem, The Roots, Janelle Monae, Girl Talk, Kanye West, Jay-Z, The Fugees, Gil Scot-Heron, A Tribe Called Quest, De La Soul,
-Baby Making Music (or just Old School style R&B): Bill Withers, Al Green, John Legend, Marvin Gaye, Barry White, (Some) Stevie Wonder...
And last but not least, that genre-spanning devil in my avatar: Tom Waits