Sun X2100 + VGA monitor = 0
Sun assumes the X2100s are going to be run headless, and therefore, configures it output via the serial console. If you plugin a monitor into the video port on this nice little pizza box, you’ll end up w/ a blinking underscore. So, some safe advice… make sure you have access to a PC or laptop w/ a serial port and the appropriate cable. 
What makes this worse is that no where does it mention this in the supplied documentation. Doh!