I've used E-prime to create computer based psychology experiments (you know, the kind where you for example show a number of pictures to the participant and record their responses to them, for example ...
I've often used Inquisit to run psychological experiments online. The software enables delivery of stimuli (e.g., text, images, etc.) and collection of reaction times. Obviously general purpose ...
I find the IPad to be a great piece of hardware that is easy to bring along and that has an intuitive touch interface. This would make it an ideal platform for many cognitive tests such as n-back. As ...