I've been doing SEO work for several years, but due to time and budget constraints, I normally stick to using just the Meta keywords, description and robots tags. I've seen plenty of pages with additional meta tags that have always seemed fake, such as:
Confirmed list? Whose would you trust? So let's start one...
The "revisit-after" metatag was a real tag -- For one small (Canadian, if I recall correctly) directory which disappeared long ago. But Webmasters and amateur SEOs so dearly wanted to believe in it that it was copied widely and spread like wildfire.
Can't speak for white-hats since I don't wear a hat, but I use only:
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <meta http-equiv="Content-Language" content="en-US"> <meta http-equiv="imagetoolbar" content="no"> <meta name="robots" content="noodp,noydir"> <meta name="keywords" content="widgets, wodgets, blodgers, golden snitches"> <meta name="description" content="Your best source of top-quality widgets within 120 parsecs! -- WidgetCo"> <meta name="copyright" content="All site contents copyright (C) 1996-2007 WidgetCo. All rights reserved."> <link rel="shortcut icon" type="image/x-icon" href="images/widgetco.ico"> <link rel="stylesheet" type="text/css" href="wcstyle.css"> <title>WidgetCo widgets -- Best widgets in the local galaxy group!</title>
Content-Type and Content-Language are only needed if you want to fully-support people saving/viewing your pages locally.
Keywords is almost useless, but still makes a small difference in some of the smaller search engines. Keep it short. Very.
Robots content is "index,follow" by default -- No need to include them. But "noODP" and "noYdir" can be used to prevent some SEs from using the ODP and Yahoo! Directory titles and descriptions if they are particularly bad, and "nocache" and "nosnippet" are ofen useful.