L.A.M.P. refers to a toolset consisting of Linux + Apache + MySQL + PHP|Perl|Python|Postgresql... providing a powerful framework for rapid development of robust solutions. Each component is open source and has proven to be enterprise ready.
The common perception of drupal is that it's powerful, but difficult to learn and use. Well, here's an article that does absolutely nothing to help dispel this attitude. more
Think of this as a snapshot into the opensource development process. Beware, this is really written for developers by developers. I include it to show drupal's sophistication and also how fast it's moving.
When you consider that only a year or so ago, drupal was extremely difficult to install and upgrade from one release to the next, you realize how fast it's moving. Get on board is all I can suggest.