IE7Pro is pretty neat as it adds a lot of FireFox like features that are missing in Internet Explorer 7:
IE7Pro is a must have add-on for Internet Explorer, which includes a lot of features and tweaks to make your IE friendlier, more useful, secure and customizable. IE7Pro includes Tabbed Browsing Management, Spell Check, Inline Search, Auto Fill Form, Super Drag Drop, Crash Recovery, Proxy Switcher, Mouse Gesture, Tab History Browser, Web Accelerator, User Agent Switcher, Webpage Capturer, AD Blocker, Flash Block, Greasemonkey like User Scripts platform, User Plug-ins and many more power packed features. You can customize not just Internet Explorer, but even your favorite website according to your need and taste using IE7Pro.
Via Greg's Cool [Insert Clever Name] of the Day