When I'm saving my ads, I save the headline only and the entire ad. This gives me the choice of searching and viewing just headlines or both the headline and the entire ad. When writing any copy, I always start and end with my headline. The headline is the draw and must be the most important part when writing ad copy. If your headline stinks, it really doesn't matter how good your ad copy is.
Chances are no one is reading it.
Another reason for cruising headline material is that quite often I am looking for nice little catchphrases for web site marketing. As I said before, my time is valuable to me, as I'm sure yours is to you. You would be surprised how much time you can save by having a database of ads and headlines at your disposal. When I need to write copy, I begin by picking several keywords that fit the type of material I am looking for. I do a search of headlines.