Screen shot of NextGen:
WP-CopyRightPro: As everyone knows, if someone wants to steal your images, they will find a way to steal them. However, this plugin is definitely a deterrent. It will prevent right clicking, as well as image drag and drop. It even protects against selecting text. Screen shot below:
Akismet: This plugin is one of my favorites and most used. It takes the pain out of managing comment spam. One of the wonderful things about Akismet is that it learns from its mistakes, so that eventually it can not only greatly reduce comment spam, but completely eliminate it. No more moderating comment spam. Akismet filters it for you and you can delete spam in one click at your convenience.
WPtouch: A great little plugin that creates a simple mobile theme for your blog. Automatically transforms your blog into iPhone application style theme - for use with pretty much any mobile device, iPhone, iTouch, iPad, BlackBerry, Palm, Android, etc.
Headspace: Takes care of all the Search Engine Optimization so that you can focus on providing great content. I like this better than All in One SEO pack.
WP Super Cache: Makes your blog load very fast. Also uses much less CPU processing.
Thank Me Later: I haven't actually installed this yet, but I think it's a great idea. Thank Me Later will automatically send an e-mail to anyone who leaves a comment on your blog. You can use this to say "thanks" to your visitors, encourage them to sign up to your newsletter or RSS feed, etc.