Shockingly, being a die-hard fan of TrekLit since the DS9 Relaunch, I'm also a fan of other long, multi-book works of science fiction.
There's an analogy I'm going to steal from (I think) tor.com's Jo Walton - plot twists are like spear points. The ones that really penetrate have long, heavy spear shafts behind them, the kind of weight built up by long, epic stories full of detail and memorable characters.
So in that spirit, here's a list of some of my favorites, and some others that are on the to-read pile, and I'm curious what you all think I've missed.
Titan, Wizard, and Demon by John Varley (3 novels)
Revelation Space universe by Alastair Reynolds (5 novels, ss collection)
Xeelee sequence by Stephen Baxter (7 novels, 2 ss collections)
Vorkosigan saga by Lois McMaster Bujold (15 novels, 4 novellas)
Commonwealth Universe and also Night's Dawn by Peter F. Hamilton (5 and 3 novels, respectively)
League of Peoples universe by James Alan Gardner (6 novels)
January Dancer series by Michael Flynn (4 novels)
Uplift series by David Brin (6 novels)
The Lost Fleet by Jack Campbell (6 novels, plus two spinoff series I haven't read yet)
There's also Brandon Sanderson's fantasy novels, all of which are in a giant shared universe and all of which play by very specific rules, so that almost counts as sci-fi. And Neal Stephenson's Baroque Cycle, which is historical fiction but feels like sci-fi when you read it.
I've also read the RAMA series and the Hyperion series, but wouldn't recommend those. Or, at least, the first book of each is stunningly wonderful and every other volume afterwards is just as stunningly horrid.
On the list to try someday:
Mars Trilogy by Kim Stanley Robinson (3 novels)
Culture by Iain M. Banks (9 novels, ss collection)
Wess'Har by Karen Traviss (6 novels)
Leviathan Wakes series by James S. A. Corey (6 novels planned - I'll read it when it's done)
So - recommendations, opinions, other series to share?