Do you mean most-searched-for on your blog, or how users arrived at your site? Do people use your blog search capability enough to make such a plugin worthwhile?
"How users arrive at my site". Don't care what users search on my site - it is a niche site so nobody could be searching crap beyond the scope and if they do - I don't have to care Is there "Suggest a friend" plugin on a page level - not site level but page level?
Google Analytics, awstats, or almost any other stats page will breakout all the keyword searches for you, so you probably don't need a plugin. I used FeedBurner's FeedFlare widgets. Includes an "e-mail to a friend" feature on each post that uses their server, not yours. Pretty handy. You can see it in action on the blog (in sig).
Thanks Anita. I used FeedFlare from FeedBurner and chose just one 'Email This' and for some reason all show up - that's weird - I will check with Feedburner and see if they can help. Rep for ya.