High Scalability Building bigger, faster, more reliable websites.

Hi, if you were to design your own highly scalable website from scratch, what technologies would you use?

Based on Web 2.0 popularity, LAMP seems to be high in the running. But would you tack on CakePHP? Drupal? or build your framework/CMS from scratch?

What version of Linux runs best for a scalable website?

Would you consider Windows and .NET? Java? Or do you want to throw a brick at me for even suggesting such heresies?

Would you prefer Postgres, Tomcat, Perl, Python, or any of that other *NIX fancy stuff...why or why not?

Please forget for the moment, "use what you know" argument. I am pretty versatile, and can look for an expert in whatever platform I choose. So all skills being equal, I'm looking for the best community support, the fastest development time and most importantly, the best scaling approach.

Let's say, for fun, that I'm planning for the website to have as many messages going back & forth as an eBay.

Definitely building this on a budget..

Jason