We got 30 or so enterprise applications, some interacting with each other. And I'd like to create a diagram to see the big picture. Which diagram should I use? System context diagram? 
Which diagram to use for visualizing connections between enterprise applications?
enterprise architecture;diagrams
If visualizing the systems and the channels of communication between systems, a component diagram is probably most appropriate.If visualizing how the applications are deployed and the channels of communication, then a deployment diagram is suitable.