I hate long episodic series. Twelve or so episodes like that are great, but when it starts getting into the twenties, I start cringing. Sitting through so many episodes with absolutely no plot progression at all seems like a complete waste of time. So that being said, it's remarkable how much I managed to enjoy xxxHolic.
The CHARACTERS were completely charming, despite sounding like broken records half the time. Yuuko was always getting drunk, Maru and Moro were always repeating everyone, Himawari was always telling Watanuki "what good friends you and Doumeki are!", et cetera. Everyone had their little niche within which they acted, but that's not to say they didn't have any character depth. Watanuki, for example, learned some sort of valuable lesson every episode, but after waxing philosophically about it with Yuuko for a few minutes, everyone would return to their usual wacky antics. You know they have depth, it's just hiding a lot of the time.
The ANIMATION is probably what won me over. I'm a total sucker for unique/untraditional art styles, (to the point where minor plot-based inconsistancies or whatever can be absolved if the art wins me over enough) and I'm not going to pretend otherwise. The character designs themselves were a little plain (plain=not terribly detailed, not plain=average), but the costume designs were superb. Yuuko especially sported some of the (if not the) most attractive outfits I've ever seen in an anime. I want her wardrobe. Right now. Other female characters also received excellent outfits, though the male cast's was more subdued. Also! I love the noodle people.
I don't really know what to say about the STORY, since it was episodic. Each episode was interesting. I liked it.
As for SOUND (anouther thing I don't like talking about), I didn't skip the OP or the second ED once. That's impressive for me. I think I'll go download them now.