I am an atheist, yet I love delving into Norse mythology. This comes from one: I am of Scandinavian descent, and two: serving in the military, we tended to hold to the "Until Valhalla" adage when we lost one of ours. I'm sitting here drinking beer and listening to Amon Amarth and the question came to me. I'm just curious to see what other mythologies others find fascinating.
Christianity -- probably because that's what held me captive for so long. When the Greek storytellers wrote the NT, they were probably laughing their asses off at some of the bullshit they were required to include. They really were the masters of story telling.
Greek Mythology. The story of Hades and Persephone.
I'm from the northern part of Norway. Nordland , we grew up with these sagas, not as a mythology or religion but as stories and faded history. Trolls became the surrounding mountains and Odin walked the shores disguised as a old man. I'm not religious but the Asa belief runs thick in my blood.
Visit Lofoten island if ever you'd like to submerge yourself in the Norse mythology.
Okay, I know this is not technically mythology, rather, fantasy, but it might as well be. I am thoroughly smitten with Tolkein's Middle Eath saga. So much rich symbolism and morality analogies, it's great!
Comparative Mythology, in the Joseph Campbell vein, but my favorite individual mythology is Christian Mythology, probably because it's the one I'm most familiar with. It's near impossible for a rational person to see the value in it as long as they insist on reading it as literal. A metaphorical reading need not conflict with science in any way.