Mm, for Amis id say Success is one I enjoyed, its kinda lightweight but reminded me of nabokovs earlier works, though Money is good and more substantial; Money and the books he did onwards are critically highly regarded though i havent read the others yet

For Pynchon it really depends on you as a reader.

Colleges tend to include The Crying of Lot 49 on syllabi as an introductory book, because its quite short; however, though short its actually really tight and heavy on linguistic and thematic complexity - it also brilliantly demonstrates the way he is able to collapse high level systems thinking with pop culture (as in his larger texts)

His first novel V is four times longer but perhaps demonstrates his genius in a more accessible way, he flips between mid 50s hipsters in NYC and chapters set across diff periods and from the perspectives of diff narrators (showing off a range of prose styles) of the previous century that demonstrate a kind of slide into decadence and inhumanity

Gravity's Rainbow is his masterpiece and is very long but a magnificent ride through the later stages of WW2, featuring streams of consciousness writing, hilarious sequences that echo classical hollywood and comic books, some heart ache and a lot of countercultural critique of the state of things in the early 70s through this work, it also presented Operation Paperclip as a major plot point, 40 years or so before the mainstream caught up

Mason & Dixon is similarly long and written entirely in old English and provides a more warmer emotional touch to Pynchons comedic and complex critique of hierarchical systems of power

Against the Day is 1000+ pages and is a multiverse novel (though not explicitly presented as such) that covers dozens of characters who become entangled in the lead up to WW1, it covers things like American anarchism in the face of capitalism and modernity, maths as mysticism, how Tesla and other inventors are destroyed by the greed of others, the birth of cinema, and a ton of other things

Inherent Vice is dismissed by some as lightweight but personally i really enjoy this stoner noir and think it features some of his best prose, it fits between Lot 49 and Vineland chronologically and features some of the same characters to make a california trilogy

Vineland is loved by some, dismissed by others, language wise its not so great but thematically its brilliant - how did the US go from hippies to 80s greed in the space of a decade?

Bleeding Edge is his most recent, possibly last novel, ive only read it once and didnt like it much, but will revisit eventually to reconsider.... set in the run up to 911 and burst of the dotcom bubble