Managing 404 errors

[SEOProPhoto]

What is the best way to manage 404 errors for pages that are no longer on the server.

For example, client deletes old site from server and replaces it with new site. Webmaster tools is reporting 100 +  404 errors form the old site.  I've blocked the 404 pages with robot.text. Requested removal in google webmaster tools. And created a custom 404 page - http://www.tvsphoto.com/missingurlexample

Is there anything else I can do?

[SEOProPhoto]

Thanks!

I've got one in place

Example:

http://www.tvsphoto.com/ga

I fairly sure its set up correctly 

[TaitLarson]

If possible you can list pages that have similar URLs on your 404 page.  Some CMSs can help you do this.  WordPress certainly comes to mind.

[RyanPurkey]

Also, be sure to have a user friendly 404 page.  404 is unavoidable due to typos, silliness and random acts of God, so it's always wise to have a highly functional page as a catchall for anything that you can't 301 redirect.

Examples
http://www.apple.com/gljasdlj
http://pages.ebay.com/gljasdlj
http://www.cnn.com/gljasdlj

[SEOProPhoto]

Thank again Barry,  Very Helpful!

[StalkerB]

301 redirect them to their new page location.

EDIT: To clarify, there are probably some links coming in to those pages or there are new page equivilents that could better serve customers.

If there's definitely no match then I'd still consider redirecting them to the home page (or even a custom landing page, rather than the custom 404 page) to preserve as much link juice as possible.