This plug-in addresses a problem I had of keeping visitors to my site interested beyond one post. Adding this plug-in's shortcode to any post suggests random posts at the end in as (in)obtrusive a fashion as you desire.
The plug-in is eminently customisable, yielding as few or as many posts as you want. It even alllows for random headers, giving the illusion the site's owner has specifically created these links for you! (Well, I guess a site owner *could* do that as well...but this plug-in will save you a lot of time! ;-) )
Very active and involved plug-in author as well: An initial bug I discovered was addressed (and fixed) within 24 hours!