OK, so I know the heat given off by the SoC (System on Chip that contains the CPU, RAM, and GPU) and the USB controller chip are well within their normal thermal parameters and heatsinks are *NOT* needed but you can't expect the kind of geek who would buy a Pi not to tinker with it!
Using the Mark 1 human finger test I found the SoC and USB chips get hot during normal Pi operation - I can't hold my finger on them for more than 5 seconds comfortably so decided to find some tiny passive heatsinks to help remove heat from the silicon.
I found these Bencool VGA/RAM aluminium heatsinks on ebay for about £1.50 for 8 of them delivered so thought why not?
They measure 13mm x 13mm and have a 3M self adhesive backing which is very thin but also very sticky. An unmodified heatsink fits nicely over the SoC with no danger of touching nearby capacitors since the SoC is tall enough to give good clearance from the PCB.
The USB chip (between the audio socket and the USB socket) is a smaller chip so I cut down a heatsink using a bench vice and hacksaw. Be careful to make sure all of the metal dust and swarf is cleaned from the heatsink and your hands before touching your Pi again or you could easily short something out! I found cutting the Bencool heatsink into a 4x3 fin array made it fit the USB chip nicely.
Here is the finished article, heatsinks are nice and warm during operation and pass the Mark 1 human finger test - I can hold my finger on them for any length of time now and they don't get in the way of any connectors or change the overall profile of the Pi.
Bencool RAM heatsinks
Bencool RAM heatsinks
Self adhesive heatsinks
Self adhesive heatsinks
Raspberry Pi heatsink cut for USB chip
Raspberry Pi heatsink cut for USB chip
Raspberry Pi 2 heatsinks fitted
Raspberry Pi 2 heatsinks fitted
Raspi both heatsinks fitted
Raspi both heatsinks fitted