check with a financial advisor here in Canada before you go to figure out what will be best for you to do. I had a meeting with one, free of charge, and we ended up deciding that it would be best for me to cash in my RRSPs, because of North Carolina state tax laws. Each state is different, so you need to find out before you leave what will be best. Also, go to the book store and find a book called "The Border Guide" its got lots of info for Canadians moving south of the border and what to do with money and such. I highly recommend it.
You'll have to notify your provincial health plan to let them know you're leaving, and they'll cancell your health card(s) at the end of the month that you leave (its illegal to continue your health benefits if you are no longer a resident of Canada, even if you plan to come back. When you come back you just notify them to reactivate it). You will need to file an "exit" tax record with Revenue Canada when next tax season comes along, otherwise you could get double dinged for
taxes, and no one wants that
You will most likely have to surrender your Canadian driver's license with the State DMV when you get your new US license, check the DMV website for the requirements in the state where you're moving to, they're all different.