Google Toolbar v2.0's popup blocker is great! Works a lot better than Alexa's, or pop-up stopper which is a freeware prog I'm using.
Here're a couple more good toolbars..
Groowe Search Toolbar:
Use Groowe to search and browse Google, Yahoo, Teoma, Altavista, Ask Jeeves, MSN and other search engines. Groowe Search Toolbar is customized for each search engine included in the list so with each engine you will be able to perform any searches that engine supports, for example image search, audio search, video search etc. It also allows you to browse site's categories or directories with unique listings for each engine.
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Dictionary.com toolbar:
Google's toolbar already has functions to search dictionary.com, but if you prefer it in a separate toolbar try it out.