Saikano - Easily the saddest relationship anime I've ever watched, though, if I was into that sort of series I'd probably watch Clannad or Kannon.
Beck - Great show, the music is fairly interesting, more specifically Koyuki's vocal stuff. The anime ends early compared to the manga supposedly, but it's definitely an interesting take for a Shonen to go (the music themematic). The director was supposedly very influenced by the song "Under the Bridge" by the RHCP.
Rurouni Kenshin < Samurai X. Samurai X is the story of Kenshin and how he gets his cross shaped scar essentially. It's a series of several episodes, 2, maybe 3 DVD's that chronology his upbringing by the swordsman Hiko, his choice to go out into the world and change things (Choshu Faction). All in all, it tells a tragic-love tale interwoven into the revolution to overthrow the Tokugawa Shogunate.
Chronologically, Samurai X is the OVA predecessor to Rurouni Kenshin, it's his days as a Hitokiri Batosai / Man Slayer, it's an extremely well done Original/Video/Animation, but on the other hand it is very bloody, but there are specific scenes that I find myself watching from time to time. (For example, you see Saito's past as a member of the Shinsengumi and some of his and Kenshin's original fights). as well as Soji Okita. ; )