http://en.wikipedia.org/wiki/Income_taxes_in_Canada#Personal_federal_marginal_tax_rates [1]
$0 - $40,726 (with $10,320 basic personal tax credit): 15%
$40,727 - $81,452: 22%
$81,453 - $126,264: 26%
Over $126,264: 29%
As can be seen above, Canada has only four tax rates. The US, however, has six.
Why hasn't anybody proposed adding tax brackets? On a relevant note, here's a potential threshold for a new tax bracket:
http://www.taxtips.ca/glossary.htm [2]
"The first $400,000 (for 2008, federally) of active business income of a Canadian controlled private corporation [3], or CCPC, is taxed at lower rates. The tax reduction is called the small business deduction [4]."
Another threshold was suggested by Oskar Lafontaine of Germany's Left Party (Die Linke): above 600,000 euros. In Canadian dollars, that would be about $1 million.
Links:
[1] http://en.wikipedia.org/wiki/Income_taxes_in_Canada#Personal_federal_marginal_tax_rates
[2] http://www.taxtips.ca/glossary.htm
[3] http://www.taxtips.ca/glossary.htm#CCPC
[4] http://www.taxtips.ca/glossary.htm#SBD
[5] http://rabble.ca/print/babble/canadian-politics/canadas-income-tax-system-so-screwed#comment-1055401
[6] http://rabble.ca/user
[7] http://rabble.ca/user/register
When you combine federal and Ontario income tax rates, there are in fact seven brackets for 2009:
Marginal tax rates:
At $36,848 - 24.15%
At $38,832 - 31.15%
At $64,889 - 32.98%
At $73,698 - 35.39%
At $76,440 - 39.41%
At $77,663 - 43.41%
At $126, 264 - $46.41%
Source: CGAO