Generally speaking, Canada does not have a business arrangement comparable to a US LLC. There is a Limited Liability Partnership, but this is only for professionals such as attorneys and accountants.
The main forms of business in Canada are sole proprietorships, partnerships, and corporations. Corporations -- "limited companies" -- are the only general-use form of business that carries limited liability benefits.
(There is also the concept of a "cooperative" but this again is not of general utility; these are agricultural, artisan, health-care co-ops and the like).
So if you're doing a Canadian start-up it's sole proprietorship, partnership, or a full corporation.
EDIT: The other folks answering this question have mentioned a "Limited Partnership" which I did not list. Note that this is not, actually, a "Limited Liability Partnership" and really very different concepts. A Limited Liability Parntnership is indeed restricted to professional associations such as legal and accounting firms.
In a "Limited Partnership", it is the partners themselves that are limited. That is, they may not participate in business operations. See http://en.wikipedia.org/wiki/Limited_partnership for a general discussion of what this means.
Although the limited partners' liability is indeed limited to the amount of their investment. This is not the equivalent to an LLC -- the US has Limited Partnerships as well.
My apologies for the omission -- I left it out since it's not applicable to the question of whether there is a Canadian equivalent of an LLC, but I see I may have confused the matter.