I like ep 12 a lot where it explains Ginko's missing eye and his name. It's one of the most touching by far.And his sensei's got a cool voice.
Here's a bit of trivia on the series.
For every 12 secs of the Mushishi anime you watch, 15,000 frames are drawn.
Every min it's 15,000 x 5 = 75,000 frames
One episode that is about 20 mins long, it's 75,000 x 20= 165,000 frames !

That's either a lot of manpower or a lot of talent.