I have also been an anime fan for many years, I started with practically the same ones you mention: Dragon ball, Rurouni kenshin or Saint Seiya. Then I abandoned them for several years, until I entered the university, classmates did not stop talking about anime and began to make me recommendations, Death note was one of them and I do not regret a moment of having seen it, it is simply a great work. I watched this anime in about 3 days, once I saw a chapter the intrigue made me watch more and more episodes hahaha. Another anime I finished recently is Claymore, this last one has very grotesque scenes and the story I also liked a lot.