I've had a US account for a few years now and they're great if you travel to the US. But..... first, you can't use any kind of ATM card with it. The best thing might be a US credit card. BMO has a US mastercard which gives you preferred exchange rates. TD is now also actually IN the US so you can now open up a bank account that is located in the US. That would give you cheques and statements too. BMO also allows you to go online and transfer funds between your canadian account at your bank here and a US location bank account, or a US funds account. The good thing will all of them is that you get the preferred rates but it really doesn't amount to much, maybe half to one cent but nothing more than that.
The only reason I know all of this is because my stepson lives in the US so we go very often and are always trying to find ways to save some money with going down to see the grandkids. Believe it or not when hubby and I first got together, we went to North Carolina and the dollar was at about 66 cents!! If oil continues its slide, the dollar will take a beating so as much as I hate the high gas prices, keep fingers crossed that oil goes up at least a little bit!! lol