I guess in the States it's important to distinguish between statutory stock option plans and non-statutory plans, because the treatment associated with the two is considerably different.
The value of the bulk of employee stock options in the States is realized through non-statutory plans. In this case they're taxed as any other employment benefit, in that there is no capital gains treatment associated with it. They're taxed at full rates. Subject to certain conditions around withholding periods, the maximum value of the benefit, and the maximum value of the benefit vesting, statutory plans will receive certain tax considerations, such as the ability to delay the taxation of the benefit until exercised.
I think on an overall basis, the Canadian system provides a more competitive treatment, in that we have put in place general conditions under which you can receive a 50% deduction on the value of the benefit.