Server Header Check

Is one of these better than the other?

[Propools]

Which of these two different server headers would you say are better, if it matters at all in getting indexed, ranked, etc.

HTTP/1.1 200 OK
Date: Thu, 05 Jun 2008 18:56:02 GMT
Server: Apache
X-Powered-By: PHP/5.2.5
Set-Cookie: PHPSESSID=7b6labls1gtb09mui1s6eimfh7; path=/
Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Pragma: no-cache
Connection: close
Content-Type: text/html; charset=UTF-8

-OR-

HTTP/1.1 200 OK
Date: Thu, 05 Jun 2008 18:56:28 GMT
Server: Apache/2.2.8 (Unix) PHP/4.4.8 with Suhosin-Patch mod_ssl/2.2.8 OpenSSL/0.9.7m mod_apreq2-20051231/2.6.0 mod_perl/2.0.3 Perl/v5.8.7
Last-Modified: Mon, 02 Jun 2008 15:17:25 GMT
ETag: "209ced7-6353-44eb07e2e0b40"
Accept-Ranges: bytes
Content-Length: 25427
Keep-Alive: timeout=5, max=100
Connection: Keep-Alive
Content-Type: text/html

Again, I'm a marketer who probably knows just enough to be dangerous. I'm just looking for that edge. ;)

[pageoneresults]

I'll bite! The second one...

Last-Modified: Mon, 02 Jun 2008 15:17:25 GMT

Although that first one has this which I'm not too sure about...

Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0

I believe that is forcing the requestor to "always" grab a new copy of the document. So maybe the first one.

Hey, I could be 50% right. I'm sure jdMorgan or one of the other Header Gurus will be around shortly to smack my hand! ;)

[Receptional Andy]

In SEO terms, neither is better.

The major difference between the two is that the first tries to defeat (user, not search engine) page caching via three different techniques. The second tries to preserve bandwidth via last-modified and etag so clients (like googlebot) don't request the content if their existing copy is current).

Another consideration is security (the second gives away a lot of server software info).

But for SEO performance, the other headers don't make any difference if you ask me. They affect users rather than search engines. Both have a 200 OK status and a valid content type - nothing else there is significant.