wheel - 12:47 am on Aug 17, 2008 (gmt 0)

Most of those numbers seem obscenely high. Timeout of 300? Minspareservers 75?(Keep in mind though, I'm no expert). I have a server with lots of websites on it, at least one (and probably more) that get as much traffic as yours does, and I have 0 problems.

My concern is that you've over tweaked your apache settings. here's what I would do:
- put your apache settings back to the default install (i.e. out of the box). Apache out of the box should have little problem dealing with your load.
- Maybe tweak minspareservers up to 20 or something. Or just a bit higher than the default apache install.
- do some googling on stuff like 'configure mysql' or 'optimze mysql'. Unlike apache which IMO needs little optimizing out of the box, you can get a lot of mileage by tweaking mysql just a bit. I've done a bit of mysql tweaking by doing just as I've noted - reading on google - and seen some excellent results.

in summary, I think you may have screwed up apache. Take apache back to what it is out of the box. Then spend some time tweaking mysql.