AJAX Finance Portal

Project is a web site intended to be a finance portal, with clean, sober look. It has to be fast and very secure, as it will handle personal and bank information of users. It will be programmed in .NET using AJAX 3.5. It will need to interact with data stored in SQL server 2008 database. This database also needs to be designed specifically for this site, to be fast and reliable, and very secure. It will have 2 types of users, ones will post what they need, and the others will browse what is needed (think of something similar to posting job opportunities) Then, it will basically involve several processes: a registration process for both types of users, a posting process for one type of users, a browsing process for the other type of users, an offering process whereby both types of users will communicate via an internal messaging service. Finally, it will need to be able to receive payment from the second type of users who will be browsing the information, on a per-click basis of the offers posted by the first type of users. The site and database will interact with 3rd party vendors of information, who will provide info for some fields on the database. The rest of the fields are filled by the site users upon registration and offering process. Thanks