KING'S QUEST VI / Sierra / PC
It wasn't the final entry in the series, but KQ6 ended up being the swan song; KQ7 was largely a mess and KQ8 made such an ill-advised transition to Tomb Raider-like 3D that many fans won't even acknowledge it as a genuine part of the series. It's easily the most solid overall KQ game; I think it came out this way for much the same reason that KQ3 came out as far and away the best of the original trilogy - these are the only two that weren't on the leading edge of both adventure game design and technology, able to use years of established technique instead of having to be the first to feel out new graphics, new gameplay interfaces and new engines.
The other part of the KQ6 success formula is that the writing is much more solid, the characters more fleshed-out and the dialogue of markedly higher quality. Chalk this one up to the inclusion of Jane Jensen, who took over the bulk of the writing duties from Roberta Williams. The story goes back to Alexander as the protagonist, and has a touch of the ingredient-based spellcasting of his previous adventure, but it seems kind of thrown in at the end for the sake of consistency rather than an important element of the plot.
Both the story and the game design work better in this one largely because it adopts the Monkey Island 2 structure; you spend the adventure hopping back and forth between several different isles, whose puzzle solutions intertwine. This eliminates a great deal of the "gotchas" found in the more linear King's Quests that kept shuttling you from area to area, and also allows you repeated opportunities to interact with characters and gives them a bit of opportunity to develop and become more well established.
Not to say some of the classic headaches of the KQ series are not present, but they are vastly reduced, especially compared to the previous game (which at times seemed to be nothing BUT a running string of "gotcha" puzzles). The infamous Sierra Hang-Ups are largely confined to two self-contained areas; a Catacombs one must explore to save a princess from a minotaur, and the Land of the Dead, which can actually be skipped entirely (at the expense of not getting as happy of an ending.) The Catacombs requires that you bring in four items that you cannot go back outside for once you enter; of course, you have no indication that these items are needed here prior to entering and running into the deathtraps where they are required. The Land of the Dead requires that you bring in a couple of these unforeseen items as well, but you are mostly steered toward them by the plot beforehand; the "gotcha" here is that there are a couple of not-so-obvious items you have to take before you leave or you'll be stuck in the final area of the game. In both cases, you find out fairly quickly that you are missing an item you should have grabbed earlier; thus you only have to replay a relatively small portion of the quest rather than starting over from nearly the beginning (as could easily wind up being the case in KQ5.) It's still bad design, but given the KQ track record it is a major step in the right direction. Deaths are also relatively rare and only random in a couple of cases that I can remember (getting ambushed by the Murderous Dwarves early on on a seemingly innocuous beach is probably the worst instance of the whole game.)
The "talkie" version of this one is actually worthwhile; no Academy Award work but actual professional voice actors were hired this time out and it's a damn sight better than the effort put into KQV. The soundtrack by Chris Braymen is also very good, rivaling that of the previous game.
KQ's main strength has always been ambiance, atmosphere and just plain good looks as opposed to story and puzzles. Usually this is due to being at the leading edge of improvements in home computer graphics, but KQ6 is running basically the same engine that KQ5 did three years prior. Still, it looks really nice, and the soundtrack is probably the best overall of the whole series. The world of the Green Isles is an odd but functional fusion of Arab/Mediterranean, Greek mythology and the usual fairy tales and children's stories. It ends up being a pleasant place to explore; though the story is still kind of to the maudlin, cliched and sappy side, the whole thing is enough to keep you interested to the end if you are an adventure game fan.
* Gameplay Video
* KQVI Recut