I have multiple posts displayed on the main page of my blog at
www.clicknewz.com , so I use the more option so it just displays excerpts. I do this because I blog several times a day, and want people to be able to scan the newest posts.
I'd say it would depend on how often you publish new posts, and how your blog is laid out.
I've seen other blogs have a static main page. I do at CorkItUp.com, but it is an "affiliate site" using WordPress as a content management system - not a "blog"...