In order for your congregation's web site to be the most effective, its development should be undertaken as a group. If your congregation does not understand the need for a web site and support it, then it will by definition not meet the congregation's expectations.
On a more practical level, developing and maintaining an effective web site is a big job. If you don't line up your resources in the congregation, you may not be able to achieve the things you have in mind, or when the crucial few people move on to other things, the web site could languish.
So, before you start thinking about site design, where you're going to host your site, or anything else, sell your congregation on the need for a site. This may well be a long process, especially if many members of your congregation have little or no experience with the Internet, but it is a crucial first step.
Next: Clarify Your Goals