And here are some of what I think are the best of the rest on the Web:

Mark Winter's WebElements, ver. 2.0

An excellent periodic table if you want data (LOTS of data) on an element.

Periodic Table Live!

This spectacular effort hosted at the University of Wisconsin is a project of the Division of Chemical Education. It contains all kinds of data on the elements, still pictures of samples, and the elusive videos (QuickTime) of many elements reacting with air, water, acid and base.

Shockwave Periodic Table

This table from the American Chemical Society employs Shockwave and includes the typical data as well as electron configurations and the ability to plot various properties versus atomic number.

Chemicool Periodic Table

Designed and maintained by David Hsu, this one has good basic data, some reaction information, etc. A nice-looking graphic interface.

ChemGlobe's Periodic Table of the Elements

Historical information, isotopes, physical and atomic properties and more. From Paul Kremer.

Molecule Man's Cyber-rific Periodic Table

Well....don't let the title discourage you! This table from the Bayer Coporation packs a lot of information into a small package. Particularly nice is the quick "what's it good for?" mouseover on each element. More information, historical and other, is just a click away.

Periodic Table from Spectrum Laboratories

Each element symbol links to a page of extensive data and background information on the element. Most of the background information comes from the CRC Handbook.

Periodic Table of the Elements

Excellent table with physical and chemical data as well as some historical background. From Eni Generalic, Split, Croatia.

Integral Science Periodic Table

Actually a suite of table styles all linked to extensive data and information on each element. More information at the site on a Windows application of the web version. From Qivx, Inc.

The Periodic Table, v. 2.5

An excellent offering from Soft Ciências, including biographical information on many scientists, pictures of most elements and a brief history of their discovery, much data, etc. Some construction still going on, but largely complete. Miguel Marques.

The Pictorial Periodic Table

Just possibly the periodic table to end all periodic tables. Includes data, background, pictures, interactive graphing and bracketed searching of properties, etc. From Chris Heilman at Phoenix College.

Elemental Spectra

This is a very slick JAVA table from the Physics Applets project at the University of Oregon. You select an element and view its absorption or emission spectrum. You can also scan through the spectrum and check the wavelength of each line.

Periodic table of minerals

From Webmineral.com, this table includes extensive lists of mineral compositions for each element, borax and phosphate bead tables, and a table of emission spectra for many elements.

The Chemical Elements

Strictly speaking this is not a periodic table site of the usual sort. There is a table, but it serves only as an entry into essays on the discovery and naming of the elements. From D. Trapp.

The Visual Elements Periodic Table

Part of a visually stunning site maintained by the Chemical Society, this table incorporates original art work along with general background on each element and some data in PDF form. You will need the Adobe Acrobat reader for the data. Some of the art work is available for download as screen savers and backgrounds.

Periodic table applet

This JAVA applet from Visual Entities give the usual information but in an interesting and slick fashion. Somewhat unique is the sliding scale for data such as discovery date, abundance, melting point, etc. Worth a look.

Printable periodic tables

These files were prepared by Scott Van Bramer at Widener University and are in Adobe Acrobat format which means they make you want to run to the optometrist when you see them on your screen but they print beautifully. All the most current information up to element 118!