Thinking of picking up some dvds in a few days. Which one of these should I buy first?

Rurouni Kenshin
Outlaw Star
Gurren Lagann
Elfen Lied
Ronin Warriors
Basilisk
Beck

I've watched Outlaw Star and Rurouni Kenshin before, so I know what those are about. The rest have been recommendations from people.

Any suggestions?