It would be nice to be able to add a description of an attachment when you attach it (instead of just a general comment). This description would appear in the Manage Attachments table next to the attachment.
Currently you can enter a general comment but that gets lost in the comment list and is difficult to locate when viewing the list of attachments.
IMHO, JIRA needs to consider attachments as things in the same time-sequence as the comments, and display them as such. Though it might be useful to also provide a section showing all the attachments alone. IIRC, Bugzilla handles attachments this way.
(It looks like JIRA is showing the traces of an original design decision that each issue would have only one attachment.)