Post #’s per page

Is there a way to have the amount of posts be a different amount depending on which page you are on?

For instance, I only want 1 post to show on index.php, but I want 5 excerpts of the posts to show on archives.php.

When I change the ‘blog pages show at most’ setting to 5, ALL the pages are affected (index.php & archive.php). Naturally, when it is at 1, all pages only show 1 post and I have to use prev_posts_link(), next_posts_link() and go through them one at a time.

Thanks,
Justin