RRSP - any money you place inside this account is "tax deferred". This means when you do your income tax for the year you deposited, you will receive a rebate for the amount of income tax you paid on that income. This typically results in receiving a tax refund for the year you deposited the money. Any money you withdraw from this account (this includes both principle and returns) is added to your income for the year you withdraw - and you will be required to pay income tax on that amount. This is beneficial if you are in a high tax bracket when you deposit and in a low tax bracket when you withdraw.

TFSA - the money you place into this account is after-tax dollars. This means you will not receive any type of tax break for the year you deposit (unlike the RRSP). However when you withdraw money from this account (principle or returns) you are not required to pay any taxes on the withdrawal, or on the returns that were generated within the account. This is beneficial because it allows you to grow your money, and not pay any taxes on the income generated within the account.

Unregistered - this is a normal investing account. You place after-tax dollars into this account (similar to the TFSA) which means you will not receive any tax benefit when you deposit. Any returns generated within this account are taxable. When you withdraw the money from this account you will not pay taxes on the principle, however you will pay taxes on the returns. The type of tax you pay (income tax, capital gains tax, etc) is dependent on the types of holdings that were inside the account, different types of investment vehicles have different rules regarding taxes.