OVAs that they should make into series.

I remember first watching the Oh My Goddess OVA a long time ago and thinking that it was really good and how they should make a full season of it. Years later I was walking next to a Barnes and Noble and saw a copy of Newtype with Belldandy on the cover. I thought wow, my wish has been granted...maybe I'll even have a goddess come out of the mirror too, hehe.

Anyways, another OVA that I thought was really good was Video Girl Ai. I definately think that they should make a series out of that but it might be a little too old...well, it still is a great story, especially if you really want a good laugh.

Does anyone else know of any good OVAs that have not yet become a full series?