Get a Russian Rat Snake. They're lively and inquisitive, but not bitey. They grow to a reasonable size, without being too huge. They eat for fun and they're very temperature tolerant. They're not expensive, either!
They look better with age as well. Very cool snakes:
Draco dormiens nunquam titillandus
“... there is no shame in not knowing. The problem arises when irrational thought and attendant behavior fill the vacuum left by ignorance.”