I'm going to second the Chronicles of Amber as being a great series that you'd probably like, although as far as the sci-fi goes it's very soft.
X Hard scifi -- decidedly not, there are many fantasy elements, but the major ones involve a coherent metaverse that explains them to a degree where they can be termed soft sci-fi - Zelazny has written a bit of harder sci-fi, but in general his stories are mostly about deep character interaction; his perspective seemed to be that technology is incidental and anything powerful and worldview-changing [personal spaceflight, etc.] is going to quickly become commonplace in the world and not need to be focused on [see computers today]. One advantage this has is that very few of his stories have the "retro-future tech" problem like some Asimov, etc. do.
X free, and reasonably legal -- I'm sure you can find torrents, and as the author is dead maybe you can morally justify it somewhat.
V good writing/art (depending on media) -- WONDERFUL writing. Zelazny is easily my favorite sci-fi author. The Dream Master is a fantastic novel (about a future psychologist who uses a device that allows him to craft dreams for his patients' therapy), he wrote many really really awesome short stories, and of course the aforementioned Chronicles of Amber.
V a deep, moving plot whit significance beyond the moments entertainment. -- beautiful plot, and one cool thing about Zelazny's writing style is that the more well-read you are the better you'll appreciate it. He writes so that being a Literature major is not necessary to understanding but you'll note little in-jokes and references if you're widely read. Paraphrased example: "I guess this is what they mean when they say things fall apart; the center cannot hold." -- reference to the poem The Second Coming by William Butler Yeats (things fall apart/the center cannot hold/mere anarchy is loosed upon the world).
V innovative, being free of a clear genre is a good sign of this.
V emotionally involving. -- of course, this varies from person to person, but I think so.
V a wide of moods and pace, generally offering many different experiences within the same work.
V good characters: deep, well developed, involving, lovable etc. -- also snarky and sarcastic (especially the protagonists, Corwin [first 5 books] and Merlin [second 5 books])
V realistic nonhuman psychology.
The main characters aren't technically human, although you don't find that out for a little while. Immortality gives one a very different perspective, and this series helped me appreciate that.
X Protagonist being artificial, like genetically engineered or AI (a character whit a human used as a base or whit a human brain dosn't count), humanity being antagonistic.
In the later books, Merlin has created a superhuman artificial intelligence posessing some of the aforementioned pseudo-magical abilities, who is a cool idea, although you don't see it grow too much. Zelazny planned a third set of books which probably would have gone into Ghostwheel in more detail (as well as other things), but sadly he died in 1994. Random, the king of Amber (and Merlin's uncle) is scared of its power and orders Merlin to kill it.
V at least one character whit a mayor role being digital, and good, but very far from human. -- Although it doesn't come into the story until book 6 or 7.
V avoids being anviliscius, and common traps like Good vs. Evil. But Tropes Are not Bad.
Ok, so in the first book the protagonist and one of his brothers go to a parallel universe to gather an army by finding a planet full of humanoid critters that worship them so that they'll obey implicitly whatever commands are given when they are led to assault another one of their brothers. Who's good again?
V Mainly serious (but not depressing. occasional comedy isn't bad.), whit a scope that is large and meaningful on some level, but not falling into a "save the world" trap. -- yep; there isn't much of a "save the world" vibe. Large, multiverse shaking stuff happens, but the characters are basically interested in 1) saving their own skin, and 2) seeing if they can politically outmaneuver one another so that they come out on top when the crisis is over.