Little Jimmy and Brent

What both of you are forgetting is this, at a 40% marginal tax rate a $6000 mortgage prepayment or TFSA contribution equals a $10000 RRSP contribution.  (You have to earn $10000 at a 40% tax rate to have $6000 after tax)

Yes in a RRSP you have to pay tax on the withdrawal, but if it is at a lower marginal tax rate than the contribution (the reality for most people), you will come out ahead of a TSFA and in my opinion the mortgage payment (you should get better investment returns that the mortgage rate). 

Of course everybody's individual situation will differ, and for some people the 'sleep at night' factor or the 'PITA' (pain in the ---) factor can sway the decision as well.

FYI, in my situation the mortgage was paid off long ago and I max my TFSA and RRSP contribution.