Custom 404 page using sitemap: Good, or Bad?

Will a custom 404 page that's a sitemap hurt?

[a_chameleon]

Hi,

I'm working on a site presently, using
MicrosoftOfficeWebServer: 5.0_Pub
X-Powered-By: ASP.NET

I'm considering a custom 404 page that's a site map.
I've searched the forums, and can't find anything reasonably recent on this particular subject.

My question:

Would a custom 404 that is a site map hurt? Help? No consequence?

TIA.

[tedster]

The actual content of the page does not matter. What does matter is ensuring that your server returns a 404 response code in the http header, and not a 200, or a 302 or whatever. The fact that a page is named something like "error404.aspx", or cotains the text "404 page not found" is no guarantee that the correct header response is being sent - and the response code is what Google will care about.

[jdMorgan]

From a usability standpoint, putting a site map or a link to your site map on the 404 page is a good idea. As Tedster says, the robots really only care about the server response code, so do check it to be sure it's a 404.

Jim