I don't have one single favorite, but I'll list some of the main subgenres I've listened to over the years in each major music genre I'm aware of.
In rock, it would be post-rock and math rock, some shoegaze, space rock, and dreampop.
In metal, black metal, blackened death metal, prog metal, technical death metal, avant metal.
In hip-hop, jazz-hop, noise-hop, abstract hip-hop, experimental hip-hop.
In jazz, darkjazz, avant/free jazz, jazzcore, bebop, hard bop, swing.
In electronic, glitch, electronic body music, minimal house, breakcore/nightcore, breakbeat, j-core, darkstep, downtempo, nu-jazz, electro-swing, dark ambient, noise.