One of the things that attracted me to anime early on was good handling of adult female characters. It is also something that I've been disappointed in all too often since.
In this sense the lead character of Moribito, the spearwoman and bodyguard Balsa is probably the best I've seen since Se Himiko in the Vampire Princess Miyu OAVs. Even better is the almost total absence of fan service despite a character design that is, ah, heavily stacked in that direction.
Balsa is quite simply outstanding as a character.
An action hero with the best of them with deep motivations for what she does , Balsa's fully realised relationships  with the supporting cast help to define her as both warrior and woman.
Also refreshing is the mother-child (possibly elder sister-younger brother) dynamic that grows between Balsa and the other lead character Prince Chagum. In the first episode Balsa is hired to protect Chagum from assassins in the royal court due to his apparent possession by a water demon. What begins  as just another job ends as so much more.
I grant that there is a romantic subtext between Balsa and one of the supporting characters Tanda , but it is a secondary element in the storyline. The relationship between Balsa and Chagum is the heart of this series, and just sings.
Chagum is also a well realised character for a relatively pampered child prince. Possibly his only flaw is that he should have whined a lot more. Tough kid, and he grows up well. Unfortunately this does almost lead to a fracturing of the relationship in some of the later episodes where Balsa  underestimates his maturity. Fortunately they do get over it.
In terms of the rest of the cast possibly the best aspect is the almost complete lack of the stupid. The antagonists  consistently do the logical, obvious, thing based on what they know. This makes for frighteningly effective opponents, and boosts the tension levels nicely.
The world building of the alternate fantasy world is fabulous. Clearly this is one novel-to-anime adaptation where there was a lot of depth in original setting that Production I.G. worked hard to hang on to.
Visually Moribito is amazing to look at, with solid character designs and outstanding backgrounds. The high definition digital transfer to Blu-Ray may have had something to do with that. :)
There are some particularly nice touches in some flashback episodes where the character designs for younger versions of Balsa were very subtly done, and this is typical of the attention to detail throughout.
I notice that I haven't really talked about the story, and I'm not going to. Suffice it to say that it is well thought out, and perceptions change throughout the series as information comes to light.
Moribito is thoroughly recommended if you can track it down.
 And more importantly for what she won't do.
 The 25 years or so of back story that Balsa has is eventually revealed and actually helps the plot when it comes out.
 In some respects it actually begins as more for Balsa but that would be telling.
 Well, for Balsa and Tanda it is mostly subtext. A good number of the other characters are rather less subtle about it, and this is a running gag throughout the series.
 To be fair Balsa isn't the only character to get this one wrong.
 I hesitate to call them villains. There's remarkably few of those throughout this series.