I would say that one of the main benefits of tags in my opinion is that you can click on them and see other items associated with the same tag. If they are really not clickable then perhaps the best thing is to display them as a comma separated list of words/terms, perhaps in a mid grey (or other suitable faded) foreground colour in order to separate them from the main content and not to make them look like they are clickable links - just the metadata that they are.
I do like the lightweight way SE tags are displayed - it's obvious enough what they are not to even need the word 'Tags' although that may not be true for all types of site. And I like that when you hover over them you get a single 'not too annoying' option at the end to go and edit them - although I appreciate that your edit interface needs to then cater for deleting only.
I also like the Behance.net way of doing the actual deleting, once in edit mode which is very clear and quick to perform. You would need a 'done' button to finish.
You could take the tag metaphor a little further and actually tie the delete button to the tag....?