I've put together a utility that I hope will be useful to Webmasters, as well as more casual Web users. It's just a page of CGI forms that access other sites; i.e. Dogpile search, Mapblast, Network Solutions, etc. What makes it cool is it is all on one page, so you don't have to have a bunch of sites bookmarked. It also only has two small graphics so it loads quickly.
The tool I find most useful as a Webmaster (if you have access to your raw logs) is the reverse IP# look-up. The access the ARIN database and will tell you where the IP is coming from.
If you get a chance to take a look at it, please do so and let me know what you think. I'm sure you will think of some functions that I missed and I would be interested to hear your ideas.