I'm usually all or nothing. If I'm going to exercise at all, I want it to be intense physical exercise and challenging. I run, but I'm constantly fighting laziness. Should I run or should I stay home? But, I always feel really, really good when I get back from an intense run.
Martial arts (Muay Thai, Jeet Kune Do, Kali, general grappling), weight lifting, hiking/trekking, certain types of dance, and I'm taking up another activity soon that I hope to be really enjoyable. It involves fire.
My favourite pastime physically are long walks or swims in beautiful wilderness areas, though, especially with my dog.