"You are not a human. You are an object."
If you were told the above, what would your reaction be? Sakai Yuji, the male protagonist of Shakugan no Shana, was thrown precisely into this chaotic situation one day while walking home from school. At the same time, viewers were introduced to the main theme of the anime. What if no one will ever remember your existence in this world. Being dead is one thing, but if everything about you will be erased from this world when you die (that includes people's memory of you), the thought alone could be terrifying to many.
While at first glance Shakugan no Shana may seem like just another anime with the protagonist being thrown into a world he never thought existed. It really make itself standout from the rest if for no other reason than the spectacular introduction to the theme of the story. The story develop itself rather slowly midway through the series as the viewers were taken back in time for some background learning that lead us to understand certain characters better (more on that in the character section). Overall there was no rush to the story as events unfold themselves in a very elegant and comprehensive manner.
It should, however, be noted that since this is just an introductory season to the Shana saga (there is a season 2 to Shakugan no Shana and there will most likely be more in the future), not a lot of questions were answered ... but many were raised and leave people in confusion at the end.
Though it can't be considered a masterpiece in animation, it is in fact still pretty top notch, especially the battle effects (flames for example, were animated in great detail and looked very awesome). If there's anything to complain about, it would be the over-sized eyes on most characters. But once that's accepted, everything else about the animation should not hurt your eyes.
While the OP were very catchy, I didn't quite like the ED much (personal taste). Sound tracks were great as they match well with the intended scenes, some can even help drive your emotion a bit. In addition, the seiyu are quite famous:
Shana voiced by Rie Kugimiya whose famous for her role in Full Metal Alchemist as Alphonse Elric, Nena Trinity in Gundam 00, and Louise Françoise in Zero no Tsukaima. Kazumi Yoshida voiced by Ayako Kawasumi who voiced in Fate/stay night as Saber, Kanokon as Chizuru Minamoto, and Otoha Sakurano in Sky Girls.
Shakugan no Shana also stars Hitomi Nabatame, Shizuka Itou, Mamiko Noto, and many many more talented voice actors/actresses.
Characters are what make this anime shine like a star. Due to the "non-rushing" nature of the show, each character (even the supporting casts) present their own background history and overtime we get to know their personality more and their "behind thoughts". This result in a very real and believable group of fantastically designed characters (both in terms of the "realism" and the "looks"). Definitely not something you see often in anime these days. The drawback is that some viewers may find it boring or made the stalled the story development.
While not quite a masterpiece level anime, Shakugan no Shana is still a show that is very successful in every single aspect. Personally, this show started out quite a bit like Busou Renkin and Bleach (while others say it is similar to Fate/stay night), but it ultimately delivered a much stronger impression on me than the ones mentioned.