If you really want my advice, I'd ignore everything I say below and go find a Thrift Store/Salvation Army Store/Secondhand Store/Et cetera and go to their book sections. You can find LOTS of good books that way, not limited to Star Trek but with a good number of them. The fact that they're tossed at the Thrift Store does NOT mean they're bad. Some very good books end up there, even old and out of print ones. Your public library probably also has a used book sale constantly or at some point.
And here's one other thing-- don't judge them all by one. All the books are different, so read more than one before going "oh, these are crap".
Oh, and another thing-- if you want to learn more about any of the ones below except the asterisked ones, PM or e-mail me. I might be able to help you with the asterisked ones, too, but I don't remember them as well.
But yeah, here's a list. These are all the ones I just went up and saw on my shelves, minus the ones that I remembered as bad and plus one that I remembered as good.
TNG:
Masks, very long ago, may have title wrong, no idea who the author is, lost book.*
Ship of the Line, long ago, don't remember author
War Drums, John Vornholt
Rogue Saucer, John Vornholt*
Guises of the Mind, Rebecca Neason
The Romulan Prize, Simon Hawke*
Spartacus, T.L. Mancour
Reunion, Michael Jan Friedman
Original Series:
Shell Game, Melissa Crandall*
Probe, long ago, don't remember. Associated with one of the movies. The probe is the thing that came for the whales in a movie or whatever.
DS9:
The Big Game, did not see book, but very good. Don't remember author.
There are also some others from the library that I don't remember, mostly from the library, but the The Captain's Table series is good; the Star Trek: Titan series is good, if a bit fantastic; Star Trek: S.C.E. (Star Trek: Starfleet Corps of Engineers) series is good; Star Trek: IKS Gorkon (Imperial Klingon Ship) series is good, and John Vornholt is good.
However, as you mentioned, these are not canonical. Some contradict each other in ways both major and minor, and some are worse than others. Oh, and there's one more uncanonical about the founding of Starfleet that is very good. I think it's called Star Trek: Daedalus. There are many others, but I can't think of them.
EDIT: I just realized that this wasn't the "book" thread. Sshould I delete this post and move this over there? I didn't mean to hijack the welcome/intro thread, though the introductee did ask me to.
+Rep 
