Those colours sound wonderful together!!! There is a teacher in my school that also uses black as the background. It looks great!
I am really torn. I have a group of kids where there are no colour issues. I love colour. I wouldn't do a patterned background with a patterned border, but I do like to change my boards a lot.
When I do a project, I match the border and background paper to the project. This is why I am torn. I am thinking I might stick with the colourful theme.
I can always switch it up later on. I was making my daily schedule titles and I use cardstock colours that match their duotang folders. Science = Green. LA = Yellow. And so on... If I did a theme I wouldn't be able to do this. Oh decisions!!!