Did you know that you can add your own cross-references to the listing? There are even several different methods for that:

Open xrefs window and press Ins
Write an IDC script Write a plugin

Adding xrefs is very useful if IDA missed some of them and the graph looks ugly. Another benefit is replicated comments.
See a demo below the cut.

http://hexblog.com/2007/02/adding_cross_references.html