What are the Pali translations for mindfulness? I know that the Pali word for mindfulness is sati as in the Satipatthana Sutta but I've also heard that there is more than one word for mindfulness that is used throughout the Pali Canon. 

Can anyone give a list of the different words used and perhaps point out the differences in emphasis or exact meaning? For instance, do all the words mean exactly the same or do particular ones emphasise a different quality of mindfulness?
Actually, the only good translation I can think of for the English "mindfulness" is Sampajañña. sam = full, pa = full, jañña = knowledge (or awareness).

Another potential candidate is yoniso (to the source) manasikara (minding).

What is pretty clear is that sati does not translate to mindfulness. sati comes from the root /sar, which means to remember or recollect. It doesn't mean to be mindful; translations like "mindfulness of the Buddha" show this to be a silly choice. "remembrance" is probably a better one.

As Bhikkhu Bodhi notes:


  Even the word sati, rendered mindfulness, isn’t unproblematic. The word derives from a verb, sarati, meaning “to remember,” and occasionally in Pali sati is still explained in a way that connects it with the idea of memory. But when it is used in relation to meditation practice, we have no word in English that precisely captures what it refers to. An early translator cleverly drew upon the word mindfulness, which is not even in my dictionary. This has served its role admirably, but it does not preserve the connection with memory, sometimes needed to make sense of a passage.
  
  http://www.inquiringmind.com/Articles/Translator.html


And there is a good article on Theravadin that I think agrees with the above both on sati and sampajañña:


  By now you will wonder how the term sati became so established as “mindfulness”. Well, mindfulness will be a result of ones practice of noting, especially during the noting…during the seeing. However, the best term translated as mindfulness is in fact a separate pali word called “sam-pajanna“, lit. ‘to know together with’
  
  http://theravadin.wordpress.com/2009/02/13/mindfulness-is-not-sati/