This is a good topic. I bet there are people out there who have read some obscure stuff but don't realize it.
I think Vernor Vinge is a good choice (I see them mentioned in the original post). True Names is not unknown (it is an excellent and prescient novella), but there people that would overlook it for different reasons. I love sci-fi but I'm not well-read enough. A few years ago I might have been able to drop names left and right, but I'll throw the Semiosis Trilogy (Sue Burke) in just because I enjoyed that one and I was thinking about it today for some reason.