What is ideal server configuration to work with CMS Wordpress and paired with what plugins?

I have a website on WP... is that at the beginning chose him.
is Apache for nginx also worth eAccellerator posts over 5 000, mostly pictures in the posts is the text.
Plugins — a classic of the genre super cache, Hyper cache and so on trifles.
in the end, around 5 thousand visitors per day drowns dedicated server 2x Xeon 2.8 4 gig of memory.
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flushing began when posts exceeded 2.5 thousand, then had to abandon the built-in media Manager, and to organize the images as 1 image in WP is stored in 3 copies + about 300-500 characters for the description of this picture in the DB...
since the extended life of the site, the server breathes more freely, but again, creeping up to 100% loads.
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WordPress database highly is not optimal under high load it is not designed, or well designed but the database will require a separate server.

on the same machine I have successfully revolves around 30 sites on django, a couple of apps for kontaktika, app to maleski on the rails, a couple of services on erlang, one for nodejs and one for racket, and in appendage to all this stuff running postgresql and mongodb.
even when this machine was launched in frambuffer flash, ffmpeg and vlc — download did not rise above 30%, and memory is always free in the area one and a half gigs, despite the fact that 3 — disk cache.
it I to what — if on this hardware wordpress can slow down — its place in /dev/trash

I think that for such a constructor, like WP, would be relevant to the preliminary question "What is the perfect set of plugins for working in WordPress?" :)

nginx as frontend for static, and Apache as backend for dynamic. Brief gugleniya how about this is configured in the application to WordPress brought me here: tech.nocr.at/tech/how-to-speed-up-wordpress-with-nginx-and-wp-super-cache/
Don't know how wp-super-cache works compared to eAccelerator, do not compare, but to be honest I doubt that will be a big difference.
A more detailed configuration of nginx and apache is a topic for an article, of which the Internet has hundreds of.
To compress things a lot better on the server than the php plugins that I love to do different CMS. In this case, since static gives nginx and compress it is using ngx_http_gzip_module.
All WordPress special is, in relation to the configuration of the server? Regular php engine, regular website. And approaches as part of the standard. Many things you can do, ranging from the banal to reduce the number of dns queries, obfuscation, and optimization of images and ending with the CDN...