Ghost Hunt Story about a girl who becomes a part-time worker with a psychic investigation team, and eventually finds herself developing abilities of her own. Good character interaction and lots of spooky stuff.
I watched the anime and the Bloodstained Labyrinth arc scared the crap outta me. (I went to bed with the lights on for a whole week after watching that arc, no joke.) How is the manga in comparison?
The Bloodstained Labyrinth arc was creepy as shit in the manga. Not sure if they toned down Mai's dream or not, but it was chilling in the manga. Urado was about as nasty a piece of work as you might imagine, too.
Mushishi Do I really need to describe this?
Adore the anime and I just started reading this recently, I'm really looking forward to it.
If you've seen the anime, you'll find the manga familiar since the anime was VERY faithful to the source. There really are very few things that were changed, in terms of both dialogue and even camera angles.
XXXholic I love this one, a take on the "sorcerer's apprentice" concept that makes Harry Potter look shallow. Plus, Watanuki is both funnier and more appealing than Harry.
Saw the anime and enjoyed it. Does the manga go further?
I haven't seen the anime so I'm not sure, but there's stuff I'm certain would not be conveyed well in anime form (and vice versa). It's a fair length, so it seems likely there are events not covered in the anime, plus the occasional mention of events in Tsubasa Resevoir Chronicles which largely don't impact the story much. A few background elements, and the reason why Yuuko and Watanuki are the way they are, but that's really about it.
Looking at the episode list on Wikipedia, it looks like there are some stories that don't appear in the manga, or are changed quite a bit at least. Of course my preference is almost always manga over anime with very few exceptions, so it's pretty clear what I'd go with.