SNIP
>>I also agree that 25 seconds is way too long for a basic web form. But, if what you are offering is valuable to the user and you give them an adequate explanation/warning, then 25 seconds (or even 120
>seconds, depending on) can be just fine.
>
>The problem with allowing users to run these reports is that if enough of these requests come in it can slow the web server down to a crawl. I think some kind of asynchronous processing which send an email would probably more appopriate if they insist of having these reports.
>
SNIP
Dan,

I don't really argue with your alternative.

But I'm not so sure that "if enough of these requests come in it can slow the web server down to a crawl" is necessarily true. Your problem here is surely I/O-boundedness as opposed to CPU-boundedness. A very good I/O subsystem can do wonders in such a situation.
I had the luxury of working with a StorageWorks (then DEC, now Compaq, I believe) array 6 years ago and it was absolutely MARVELOUS! And imagine what improvements have been made since that time!