Should I watch these anime?

Well, out of all of those, I've only seen Madoka Magica. I highly recommend it, it's one of the best animes I've ever seen. The música is gorgeous, as well as the plot and characters. The series is fairly short, but there are cine as well! I really think it's a must-watch for all anime fans, even if they aren't fans of Magical Girls.

Sorry I couldn't really help with the others!

ive only seen D. Gray Man and Deadman Wonderland. But i do highly recommend them :)

Well tu should definitely watch xxxHOLiC, D. Gray-Man and Deadman Wonderland since they're great anime. I wouldn't know about the others since I never saw/heard the other anime listed here.

Higurashi and Higurashi no Naku Koro ni are actually the same anime. Well, I would reccomend the aforementioned series, xxxHOLIC, and Puella Magi Madoka Magica.

I would recommend lectura the manga versions of Pandora Hearts, Deadman Wonderland, and D. Gray-Man to that of the anime.

The only I would NOT recommend is Higurashi.

And I've never seen Deadman Wonderland so not sure about that one.

But the rest are really good and tu should definitely watch them!

I would DEFINITELY recommend watching XXXHolic and D. Gray-Man