I wrote down my opinion a long ago, but I changed a lot, so I deleted my post, let's see it now...
Who are your favorite authors?
That doesn't changed too much. J.R.R. Tolkien, Jack London, George Orwell, Joseph Heller, Alexandre Dumas, Umberto Eco, Salman Rushdie, George R.R. Martin, Shakespeare, P.G. Wodehouse, Douglas Adams, Oscar Wilde and finally, Michael Scott.
What are your favorite genres?
I don't like specifying to genres... Fantasy's once been worth reading, but now this is all stained in my opinion. Anyway, the genres I like are: historical, paranoid, saga (and I mean it in the original meaning), dark fantasy. I've always liked dramas, myths and poems too (even if they don't count as a genre).
What is your all time #1 favorite book?
What a terrible question! I don't rank the books I've read, I don't make gradiations... I have the books I like and the ones I don't, and I have the ones I like more than others. But I'll never have a #1.
What else are you reading right now?
I'm reading A Feast for Crows, fourth of A Song of Ice and Fire, eagerly waiting for the fifth.
If you could name one book that left you speechless or made a huge mark on your life or imagination, what is it?
I couldn't name one! I read several books that really left a mark on me, but there are so many of them! Tolkien's Narn i Chîn Húrin (The Tale of the Children of Húrin), George R.R. Martin's A Song of Ice and Fire, Shakespeare's Twelfth Night, Richard III and Hamlet, Orwell's 1984 and Rushdie's Midnight's Children is certainly among those.
Not asked, but if anyone cared about favorite series:
A Song of Ice and Fire, Lord of the Rings and Silmarillion (with everything else), His Dark Materials, Jeeves-novels, Diaries of Adrian Mole...
And Multiverse: I deeply agree about Harry Potter.