I'm gonna slight Jorge and just rave about Vlad and Tommy boy.
Nabokov was a genius!! Speak, Memory is my personal favorite, a singular gem. For some reason, I just love that he hated Freudians. In his forwards, he would NEVER miss an opportunity to slam what he called the "Viennese Contingent", LOL!
It's also impressive beyond belief to me that, like Joseph Conrad, English was not this White Russian's first, or in his case even second language (like most educated Russians of his time, that would be French).
While I suspect that 100 years from now, Nabokov will outlast and outrank him, I, personally looooove Thomas Pynchon, especially his magnum opus, Gravity's Rainbow. Tyrone Slothrop, LOL, what a great name for a hero! I saw where you recommended The Crying of Lot 49, eh, to each his own.
While the 700 page sprawl of GR is often sloppy and disorganized, it gives Pynchon room for his million horsepower brain to repeatedly explode in dazzling verbal pyrotechnics. There are probably more than fifty places in that book where the man just catches fire and he just soars off on some mad tangent, his prose gone taut like the best of the best of the best of poetry, for two or three dense pages sometimes. It's f*cking awesome!!
When you're talking about heavy hitters in the English language, you have to include Samuel Beckett, IMHO. His play Waiting For Godot is seminal, to be sure, but my personal favorites are his earlier pre-war novels like Murphy, Malloy and Malone Dies, which were all written directly in English. Many folks don't know that Godot and all his later plays were written by him first in French, and then translated later by him into English. What an Irish git!!
My favorite anecdote about Beckett (possibly apocryphal) has him walking through the streets of Paris on a gorgeous Spring day. His friend says, "What a day! Makes you glad that you're alive, doesn't it?"
Beckett replies, "I wouldn't go that far."