My favorite artists that sort of helped me understand other music are Bowie, Prince, Kraftwerk, Santana and Umm Kalthoum. Currently i've been listening to Mayra Andrade which is introducing me to different sounds..
Also Bluegrass played a huge role in my appreciation of stringed instruments...i took that appreciation with me to the roots in north africa and the middle east. I got into Tuareg and bedouin sounds in a big way out there. also gnawa music... love it. everyone should give Gnawa Diffusion a try. excellent stuff
2. the world without us
3. the rum diaries
4. the Holy Quran
5. thompson, omar khayyam, kerouac, homer, tolstoy