These adventures of a six year-old boy and his pet/ toy/ imaginary-friend tiger are philosophical, satirical, thoughtful and witty in a way unlike any other comic strip I've ever seen. All backed up by masterful inkwork. And very funny. I picked up a compendium book of the strips (There's Treasure Everywhere) in Oxfam for £1.50.
A couple of strips from this book. I love the innocence captured in this one, which gives the book its title:
After 10 years in newspapers, Bill Watterson, the strip's creator, admirably knocked the whole thing on the head in 1995, and always refused to merchandise the characters.
Here are a top 25 Calvin & Hobbes strips from a blog names Progressive Boink:http://www.progressiveboink.com/archive/calvinhobbes.htm