What should be on the list (imho) but was missing:
Yep, IMO, most of those should be on the list. (Simmons is in the poll, though.) I'm not directly familiar with some of them and don't love all those I am familiar with but, in terms of reputation, they have it. Now that you mention them, probably the most striking omissions to me are
The Man in the High Castle,
To Your Scattered Bodies Go,
Eon, and
The Mote in God's Eye. Aside from those, while not as striking an omission, I love the Morgaine books. (Speaking of striking omissions, I'm not a fan but it is kind of amazing
A Canticle for Leibowitz, which Extollager noted, didn't get mentioned in time for the poll.)
Also, just as Extollager noted Black Gate had a
Mission of Gravity-relevant post, they've also just posted this on the Ballantine/Del Rey "Best of" series:
Keith West on the Ballantine Best of Series and Why We Need it More Than Ever. The main article it's referencing is
An Ode to the Ballantine Best of Series and Why We Need it More Than Ever.
An observation on the poll (and apologies if any of these comments or lobbying are improper while the poll is live): I wonder if there isn't some poll fatigue. It makes perfect sense for more essential things to have been mentioned earlier, generally, and, thus, for things earlier in the poll to get the most votes and some things late in the poll have gotten several votes but, even so, there really seems to be a massive weighting of votes towards the stuff listed earliest in the poll. I wonder if some people don't just start checking things off until they get bored or run out of votes.
Also, I
have to wonder if people are even understanding what
The Past Through Tomorrow is, though I would have assumed it would be familiar to every SF fan. That is an omnibus of all of Heinlein's Future History stories (excluding
Orphans of the Sky) - allowing for a non-FH story or two swapped out with an FH story or two swapped in, that's
The Man Who Sold the Moon,
The Green Hills of Earth,
Revolt in 2100, and
Methuselah's Children in one volume(!) and, yeah, I know, it's just my opinion but this
has to have about as many votes as anything else in terms of a touchstone of the field.