1000 Novels we all must read: but where to begin? which ones have you read so far?

http://www.guardian.co.uk/books/2009/jan/23/bestbooks-fiction

1000 novels everyone must read: the definitive list -

this of course begs the question: WHY - why must I read these? who says so? what for?
Ok then - what are my reasons for reading, for choosing to read the books I read? Which books have you read on this list and why? Was it worth it? Which were the most worthwhile and why?

And - which books would you add to this list?