Very interesting subject. I think V-tog said it best in that attachment is an essential part of being human, and I'd go further by saying that only through attachment can we really hope to bring our divided race together. However, there certainly are forms of attachment that are not constructive, that alienate or degrade that which is creative or 'good'.
In the Star Wars movies for instance, the Jedi fell to the machinations of the Darkside, and from my perspective a very large reason for their failing was their almost mindless devotion to the concept that all attachments are the path to the Darkside. By working so hard to stave off that which you believe is wrong (but is actually inherent to humans), to the point where you hide from it and ignore it, you're only hastening your own end.
Now in the rejuvenated Jedi Order that Luke created, the age restriction was removed, as was the restriction on Jedi having attachment and romance in their life, and this led to a far more compassionate and healthy way of living. There is of course nothing wrong with someone making the personal choice to abstain from connections, but to deny that attachment exists is a serious flaw to any form of living.
However:
“Most of our troubles are due to our passionate desire for and attachment to things that we misapprehend as enduring entities.” ~Dalai Lama
Now in this sense I think the concept of non-attachment or detachment can be seen in a different light. The goal isn't to remove yourself from all emotions or purge yourself of feeling, it isn't even to deny yourself feelings that you have. Reaching detachment is reaching a point where you still have feelings, you can still love and be sad and feel anger, but these things are passing. They simply exist, they simply are, and one takes them as they are in the moment, being at peace with the fact that those attachments/feelings exist, but being able to continue without letting those things guide you one way or another. They simply are. Not good. Not bad.
Am I making any sense...?