This is ... incredibly difficult.
Keeping to
favourite books (which don't necessarily overlap with
books I've appreciated or
books I consider important or
books I really should mention because they're more high-brow than those I am actually going to list but I won't because, well, they're just not truly my favourites), this is probably the best I can currently come up with.
- The Skulduggery Pleasant series - Derek Landy
- The Three Musketeers, Twenty Years After and The Vicomte of Bragelonne: Ten Years Later - Alexandre Dumas
- Harry Potter - JK Rowling
- Sense and Sensibility - Jane Austen
- The Hobbit - JRR Tolkien
- The Mysterious Island - Jules Verne
- The Silver Metal Lover - Tanith Lee
- The Bartimaeus Sequence - Jonathan Stroud
- Leatherstocking Tales - James Fenimore Cooper
- Jane Eyre - Charlotte Bronte
Oddly enough, my love for practically everything on this list either dates from my childhood and teenage years or from the last decade or so. Other than Harry Potter, I cannot even remember anything I read between, say, 1994 and 2004, and I'm pretty sure I read quite a few books.