I'll just add that we (LinkedIn) are a JVM shop. Amongst our weaponry are: java, scala, other intriguing languages, hadoop, voldemort, OS X dev boxes (with scads of memory), lots of perks and fun projects.
LinkedIn is a great place for web developers (front-end) as well. In 7 years our team has only lost one due to chrun, the rest all still work here. Feel free to reach out if you are interested. http://www.linkedin.com/in/scott
We also have many open source projects to work on: http://sna-projects.com
We are located in Mountain View, nestled in amongst the sprawling Google surroundings.