Scalable applications

Been working with some new technologies lately and I’ve come to the conclusion that for building a scalable webapp, the combination of Java(Servlets/JSP), Spring, Distributed Hibernate caching, and Horizontally Partitioned Mysql Databases hits the sweet spot.
I’ve heard several people choosing Ruby on Rails and Python for speed of development, but if you have some decent Java engineers there really isn’t any reason why you couldn’t have something up just as fast with a tomcat application server.
The big plus is that when the surge of traffic hits, it’s now very simple to scale the site with increased commodity hardware and there isn’t any need to rearchitect the code.
 The one bit of code that I’m looking to get a bit more mature, that completes the picture, is Hibernate Shards, which is coming out of Google. Once this piece is ready for primetime, you’ve got a rock solid base to build applications off of.