Currently Being ModeratedFeb 6, 2013 8:01 AM (in response to Dundee15)
Yes, you can use a non-Apple USB keyboard and mouse.
See here for some mapping definitions.
Yes, you can use external drives with a Mac Mini. You will have 4 USB 3.0 ports, Firewire and Thunderbolt ports. Also, your Mini will come with an HDMI->DVI adapter so you can use the DVI port to plug a non-Apple monitor into using a DVI cable. You can navigate here to view the back of the Mac Mini for all the available ports.