Stirring the pot a little more (or a warning), be aware that if you have had a conviction that is considered a felony in Canada in the past 10 years (example, a DUI which is not a felony in the USA), Canada may not let you in (not picking on Canada, the USA has equally stupid rules).
Details here
http://www.tiac-aitc.ca/english/customsandborders.asp
BTW, the US and Canadian "criminal" databases are NOT linked, so a DUI in the USA 7 years ago (where it drops off the record) will not show up in the Canadian search, ditto one 5 years ago (not agruing morality and DUI laws here, just letting folks know - hint, don''t admit to anything)
As for the paperwork for crossing the border, the real issue is coming back to the USA. Until the end of this year, a WA Drivers' License (but not OR, long story regarding illegal workers getting DLs) might work. Or you might be detained for hours. Birth Certificate (certified, not notorized) or passport is the best bet. "A driver’s license, voter’s registration card or Social Security card is NOT valid proof of citizenship."
If you are taking any children under 18 with you, look up the requirements! Weird laws to stop child abductions. A frind of mine got hit by these until his wife faxed pemission for their kids to go to their vacation house in Canada.
Full details here
http://travel.state.gov/travel/tips/regional/regional_1170.html
FYI:
Alcohol
As long as you meet the age requirements set by the province or territory where you enter Canada, you can import, duty and tax free, one of the following: up to 1.5 liters of wine, or 1.14 liters of liquor, or 24 x 355 milliliter cans or bottles (8.6 liters) of beer or ale.
Tobacco
If you meet the age requirements set by the province or territory where you enter Canada, you can import, duty and tax free, 200 cigarettes, 50 cigars, 200 grams of manufactured tobacco and 200 tobacco sticks.
I'll have my full duty-free allowance crossing the border (OK, not 50 cigars, maybe 10).