When viewing bib and holding records, there is a link to edit mode that takes you into the metadata editor. If you are viewing an item record and realize that you would like to change it, you have to cancel, go back to the list of items, and then select edit from the action menu.

It would be handy to have an edit button on item record when viewing it, even though that isn't in the metadata editor.
It would be handy to have this feature in MANY other fields--there are lots of times when I click on something in order to have a look, and then have to back out and re-enter in edit mode. If I have the right to edit something, I want there to be an edit button there when I'm viewing the record.