Rurouni Kenshin is definitely the best for me. It has left the greatest impact. The development of the characters is moving. The emotional depth, the historical context, the epic spirit and the philosophy of life behind it, it's unique. I mean the oldest one (from the late 90s), which I only discovered recently and simply surpassed all I had seen from anime (and I had seen good ones like Saint Seiya, but hey, this is nothing compared with Kenshin).
It’s a work of art. Every time I watch some of it again I discover something different. I hope some of you will join me in praising it. I would hate to be one of only few who appreciate that...
... and please, if you know something as good as this anime (preferable historical settings too), do recommend it! Arigatou!