I am a little “anti-plugin”. I try to avoid adding plugins to my blog if I can avoid it. Mostly because I don’t always know what they are doing and you never know what people are doing to your blog once you click Activate, and so I really enjoyed a post I found thanks to Weblog Tools Collection that shows off how to add Gravatars to your blog without using any plugins.
The tutorial, by Connor Wilson requires a bit of theme editing knowhow, but isn’t all that difficult to do.
The basics are that you need to create a MD5 hash of the commenters e-mail address as the URL for the image that you want to pull. Very simple, and very impressive. I tip my hat to you Connor.