A Room With a View by E.M. Forster.
Just watched the most recent adaptation for tv and thought it was great. In a nice little circle of things, Lucy Honeychurch was played by on of the girls in Fingersmith, there was a lady author at the beginning that was played by Sinead Cusak, who was Mrs Thornton in North and South (and such a different character), Mr Beebe was played by the guy who is Mr Beazley in Harry Potter and Old Mr Emerson was also in Harry Potter and was the that chappy that turned into a rat.
My 3 year old son was sitting watching the last bit with me. And there is a sex scene (very tastefully done). He had been sitting quietly watching with me (a rarity, but I had promised he could watch something if mummy got to finish her show), and all of a sudden he say "Mummy, what's going on?" Taken by surprise, I took a deep breath floundering as to what to say, when the next shot is of them laying back in bed, and he says "Oh, they are going to have a sleep". Phew!