Not underrated, still a famous movie all around the world (eventough Tarantinos weakest by far).
With "underrated" in this case I mean great movies, the majority of the population probably hasn't even heared about. Which sucked completely at the box office and maybe didn't even make it to foreign markets, evntough they were awesome watching them.
From my list:
Escape from Absolom, Deep rising, Ghost ship, Eagle eye, Reign of fire, Flight of the phoenix (remake), Pitch Black, Hidalgo, The life of David Gale, In Bruges, Joyride, Outlander, Premonition, Screamers, Stigmata, The crazies, The hunted, Thirteen ghosts, Deep blue sea...
are some of the flicks I'd heard little of, but enjoyed watching.