So difficult to choose just ten. I'm going for books I've really enjoyed and that have stayed with me, rather than a list from "the canon" re upthread discussion. So ..
Pride and Prejudice Jane Austen. I also love Persuasion but P&P cheers me up more.
Middlemarch George Eliot. Such truthful character observation
The Old Wives' Tale Arnold Bennett. A great small-town drama.
Barchester Towers Anthony Trollope. The whole set of Barchester Chronicles if that's OK.
War and Peace Leo Tolstoy. I agree with a PP. It's not a difficult read; it's great. I don't understand why people are so daunted by long books. Just think of it like reading two or three shorter ones.
Sunset Song Lewis Grassic Gibbon. All Scottish kids of my era read this at school, and it's still a strong memory from my teenage years. I must reread it soon, and I hope I still think it's as good.
A Fine Balance Rohinton Mistry. Some people find it depressing but I think it shows the strength of the human spirit in unimaginably challenging situations.
Diary of a Nobody George and Weedon Grossmith. Subtle and touching and funny.
My Life and Hard Times James Thurber. Ageless observational humour.
Can I squeeze in Ballet Shoes by Noel Streatfeild as well? I read it again and again as a child. I just found it magical (and didn't question the sort of poverty where one scrapes by with only a nanny, a cook, two tutors and one maid!)