The critics at Time magazine have published their list of the top 100 English language novels since 1923. You can find it here. Better than some of these lists, I've read 27 of the 100. Lists like this remind me that I am not, relatively speaking, well-read.

The 27 I've read and how I rated them on Time's reader response (1-5, with five being the hightest, though we couldn't do half points, I am adding that myself):
American Pastoral -- 4.5
Atonement -- 3
Beloved -- 5
Blood Meridian -- 4
The Catcher in the Rye -- 2
The Corrections -- 2
Go Tell It on the Mountain -- 4
Gone with the Wind -- 3
The Grapes of Wrath -- 5
The Great Gatsby -- 5
The Lion, the Witch, and the Wardrobe -- 5
Lolita -- 5
Lord of the Flies -- 4
The Lord of the Rings -- 4
Midnight's Children -- 4
1984 -- 5
Portnoy's Complaint -- 4
The Power and the Glory -- 4
Rabbit, Run -- 3.5
Slaughterhouse-Five -- 3
The Sound and the Fury -- 2
The Spy Who Came in from the Cold -- 4.5
Their Eyes Were Watching God -- 5
Things Fall Apart -- 5
To Kill a Mockingbird -- 5
White Noise -- 5
White Teeth -- 2