I quite simply went for the cheapest presoldered Nano (with USB) I could find on ebay -
http://www.ebay.co.uk/itm/171204215696
Also got 2 Pro Minis which need a USB to Serial adapter (that I already have) which only has the serial headers soldered -
http://www.ebay.co.uk/itm/251336801022
I'll probably use the Nano for messing around since I can easily plug it into a breadboard, then use Pro Mini for anything more permanent.
I also bought a bluetooth transceiver thing to maybe make it wireless.