if you want something exotic, you can try the saf yacht club at changi. fantastic view of the sea and a marvelous poolside and really not very expensive. around $3k for the venue (not incl food) and even got yacht march in and walk down the aisle in the pier. fantastic! http://www.safyc.org.sg/index.php?option=com_content&task=view&id=38&Itemid=96
Fort Canning Hotel. The service is very good, the sales person did a number of follow-up smses. Although I didn't choose to have my solemnization there due to other reasons, I would recommend it just for the service.