Mingus Oh Yeah was my gateway drug (Hog Callin' Blues is just magnificent - Roland Kirk!!!), but Ah Um is probably a better entry point; very accessible and wide-ranging in content/style it surely has something everyone would like.
Mine was the live version of Moanin' from the Mingus Big Band 93. So much energy, it made me jump off the sofa and dance. I never ever ever dance! It must be played loud.
Goodbye Pork Pie Hat has to be the sexiest song ever. It's music for love making.