In general, I find it really annoying I can't find specific short stories/novelettes available for $1-2. Which I guess I consider reasonable for older stories.
I have an older edition of True Names and I didn't realize it was hard to get your hands on. IMO it's the author's best work.
I think a fire upon the deep is his best. You can (logically) read the second chapter (introducing the tines) as a self-contained short-story, and it's brilliant: the way it introduces their issues, the characters and the glorious plot.
I agree about Fire Upon the Deep. Something else in a similar vein is the prologue for Hogan's Code of the Lifemaker which I'd argue is significantly more interesting than the book as a whole.
True Names and The Lifecycle of Software Objects are two of my favourite pieces of writing.