I've just got my parallella and followed the http://www.parallella.org/quick-start/ but there is a problem - when i've plugged it in it does flash pretty lights, Ethernet cable is flashing and so on but it doesn't lease address from my router via DHCP or gives any output via HDMI (screen yells "no signal" at me).
I tried the headless, followed the steps (and triple checked that I've followed them right) but still no dice. Then I've used the sd image from parallella ftp (ftp://ftp.parallella.org/sd_images I snagged it via torrent as ftp was painfully slow) and that also arrives at the same spot.
I am using 2A, 5V DC PSU as recommended.