Justin Blanton shows how to limit the number of posts that are displayed on the index page of your WordPress 1.5 blog. You can set the Show At Most option but that is for all pages including archives.
One of the first things I noticed when I started to setup WordPress was that there was no way to control the number of posts displayed on the index page from the admin panel. Yes, there is the “Show at most” option, but this is a site-wide variable and works to treat all of your pages the same.
To limit the number of posts on your index page while allowing all other pages to look to the “Show at most” setting, check out Justin’s hack.