David Gerrold gets my vote. Oh, he's around but his master work is largely unheard of. He wrote the Trouble With Tribbles episode of Star Trek, and one of his books was made into a movie (Martian Child) which I haven't seen...
But his Chtorr series is *amazing* and, sadly, out of print. The Chtorr series is about an alien invasion except the invasion isn't a war in the traditional sense. It's an ecological war and the Chtorran lifeforms are about half a billion years older (more evolved) than our's. Their microbes have been replacing our's and it's gone increasingly further up the food. There seems to be no obvious sentient intelligence in any of the aliens, and there's been no evidence of anything like starships. No one knows where it's coming from, they just know it's not terran.
I really enjoy the writing style. It feels like the author is enjoying himself when he's writing these books, and that makes you enjoy it even more. The books are all from the perspective of the main character. It can get introspective (fine by me) and also it can be preachy at times with the author preaching his ideas. A lot of which I find fascinating regardless of whether I agree with them or not, but there are definitely times when it can get tiresome.
4 books have been written, with each book being superior to the previous book. For something like well over a decade, the 5th book has been marked as "coming soon!". No one really believes it anymore, but hey, duke nuke 'em 3d is out, GNU/Hurd is more or less usable, so why not?