Just a note on the $25.00 GiftCertificate.com Marriott certificates; I amassed $450.00 worth of coupons very quickly in late November and early December. When I tried to redeem another Supercertificate near Christmas, they cancelled my order citing one offer per customer. I don't think I will see the bonus certificates either that they promised as the customer rep that I spoke to seemed to be a bit ticked that I would even dare to ask. Oh well, they'll get over it.
Travelweary, are you converting your vacationmiles for American Airline miles? It wasn't clear by your post, but if you convert to AA miles, you will get 10,000 Hilton points per 5,000 mile redemption, by far better than the 1/1 point ratio when redeeming Mypoints at the Hilton redemption site.