Knowing what technology to use when and how to apply it to achieve the desired business objective. This is "the art" based on the science.
These are the tools of our trade. This is the technology we focus on. Whether you want to use a commercialy supported products or if you are considering the cost savings of Open Source technologies.
.NET, Spring, Rails
Oracle, SQL Server, PostgreSQL, mySQL
JBoss, .NET, Resin
C#, Java, PHP, Ruby, SQL, XML, HTML
Cisco, Juniper, SonicWall, DELL, SuperMicro, Isilon