[Lemur]

So quite frequently the first thing I reached for on a web server was Apache. It was just what I learned and knew, so I assumed it was the best for the job. A bit more research in, and a years worth of experience and I'd swear by NginX.

I can cover NginX, but would others be willing to give a more detailed description of alternate web servers?

NginX is Russian based, extremely efficient at handling static sites, and uses non-blocking processes. This leads to drastically less RAM and resource usage as compared to a typical apache solution, which means it can handle some truly epic sized user bases. The problem being that you have to proxy dynamic content to other handlers, such as php-fpm, cgi, passenger, and etc.

One of the solutions to hosting dynamic content while taking advantage of the static strength is to use Varnish as a chaching system to proxy traffic to NginX's dynamic handlers only when necessary.

For a quick lightweight I'd recommend it to much of anyone.

http://wiki.nginx.org/Main

Some other alternates that I don't have experience with:

Lighttpd
Cherokee

Anyone want to cover some others? I haven't had time to play with them much.

[no2pencil]

Not sure that I will provide much more insight

I use nginx to bind to port 80 & handle all outside requests. But because I have not devoted enough research time to it, I only use nginx to serve html sites. Any php based site is then handed to apache on the same server on another port.

[Lemur]

With NginX you could always use PHP-FPM to handle the PHP requests, and use Varnish as a back end cache that will forward more static requests to NginX itself. This type of setup works great for what I tend to call partially dynamic sites such as wordpress permalink pages. Most content is really static, and rerendering the PHP every time is a waste of valuable resources. That was the concept behind Varnish caching and serving up static versions of such pages.

Combine those three and you have a fairly robust web server that can take some pretty heavy traffic.