I'm not sure how good an intro the OVAs are. They are excellent, but a lot of their impact on me came from how much Kenshin had changed. I think its a better idea to watch the series first, so you have an established idea of Kenshins character.Rivana said:The backstory Samurai X is also a really good intro into RK.
Anyway, my recommendations:
Full Metal Alchemist
Rurouni Kenshin
Elfen Lied
Neon Genesis Evangelion, I like it, some people don't but you at least need to form an opinion of it.
Vision of Escaflowne, the most romantic story involving giant robots I have ever seen.