I'm run a project which distributes open source software (nightly development builds of XBMC and OpenELEC - http://www.xbmcnightlybuilds.com ). I'm in the process of expanding this to include some new open source Raspberry Pi projects too.
I currently have mirrors in the UK,EU and East coast US, but I've had requests from users for something more central US or possibly West coast.
Looking for 512mb and 150-175GB disk space, 100mb port - gigabit port is a bonus. Must have good outbound connectivity. I've recently changed how my cdn works, its hard to be exact on bw requirements. They shouldn't be significant 500Gb is probably enough - but lets say 1Tb to be safe.