I can't really think of a "best" one.. Not much on that appeals to me - except documentaries; things on Discovery Health; National Geographic; A&E; etc..
Speaking only for myself, television hasn't been "good" in a long, long time..
I don't know if there is a US version but Discovery Canada had two shows, Canada's Worst Driver and Canada's Worst Handyman, that are hilarious and scary at the same time.