I have been trying rather unsuccessfully to get Gravatars to work on my blog. The built in get_avatar() feature seems to be generating an incorrect md5 hash; so isn't retrieving the correct Gravatars. For example, the md5 for my email address is; 08cab17d20de8d790a0fdaad3146da98; but WP generates: cfc6467002ed3982abbe8d6e5481c03c. I added he WP_Gravatar plugin which worked fine, displaying my Gravatar but it's hard to incorporate the plugin into my template design so I have ditched the plugin.
This is what I have in my functions.php file to generate the comments loop!
I have show Avatars enabled in Settings > Discussion, maximum rating set to "X" and mystery man set as my default avatar. I have the correct email address (for the Gravitar) set as my email address in General Settings, and have even checked the comments themselves for the correct email address. I know my Gravatar works fine as it displays on other sites, just not my site.
I guess that I am missing something here...