Every reader I know has a decent sized list of "must read" authors. While mine have changed a bit over the year, there's a fair number that always remain on the list.
Madeleine L'Engle and the Wrinkle in Time Series
Jim Butcher and the Dresden files
J.K. Rowling and the Harry Potter Series
Audrey Niffenegger and The Time Traveler's Wife
Eoin Colfer and the Artemis Fowl Series
Diana Gabaladon and the Outlander Series
If you ask me what I'd recommend, I'm like to pull on from that list.
Who is on your must read list?