Starring will not work. In a week you are going to be asking for a gold star as well so you can differentiate between your close friends and your really close friends. This will continue and quickly become unmanageable.

I don't think groups is the solution either. It is a solution but most likely not the best due to the fact that there are a million combinations of groups I can put together using my friends. Ideally these groups would not be long lasting and I could create them on the fly.

That doesn't resolve the context problem. Your close friends from school aren't your close friends from work. The two are not necessarily going to intersect. Starring is to one-dimensional, hence groups. But groups are a pain to manage. Pick your poison...

Facebook already lets you choose to ignore some people and view more of others. I personally don't use it, but my more serious Facebook-using friends do.