Blu-tack is one of my most favourite 'tools' when soldering single/multiple circuitboards, a piece on each corner of the board ensures it'll stay fast on the desk when soldering but can easily be picked up for closer inspection or rotation etc., I've used those "helping hands" in the past but I found them to be frustrating, too fiddly to setup and if you start rotating/moving the arms too much they loosen
I have a small desk vice with suction base for holding things besides circuitboards, rarely use the suction because it's solid metal so has a really nice weight to it.
As for magnifying stuff to look at it closely, I tried using a desk magnifyer with ring bulb but couldn't get used to it, this however is extremely useful when doing SMD work -
http://www.dealextreme.com/details.dx/sku.2823 (just wish they'd used actual glass because the higher mag lenses distort what you see too much) and when I want to see
really close I have a stereo microscope to hand.
The 'tool' I carry with me literally everywhere (besides my 'wire stripper' nails) is my
Photon Freedom Micro, best single 5mm LED torch I've ever seen/used. Waterproof, very bright, very tough, very reliable and has a lifetime replacement guarantee to boot. Ideal for inspecting circuitboards along with a magnifying glass as you can shine it behind to see if there are any shorts, and great for going literally anywhere at night.