Welcome to FT! You may wish to amend your post a little as someone will come along to tell you that your June 2010 vacation is long over.
Marriott has been quite difficult about cancellations and refunds (I presume you have cancelled but not received a refund?) I think this is a tricky one. Travel insurance will probably not apply because a disinclination to travel is typically not covered. I don't know if a chargeback will work because, again, you decided you didn't want to travel, in theory the hotel was willing to accommodate you. If the hotel isn't willing to budge, have you considered asking them for a credit for a future stay?