When the dollar was at par last year, we decided to open a US account (we're at Canada Trust). Every week, I'd "slide" $25 Cdn into the account from my computer. Whether the dollar is up or down, I'd make the transfer. I just got tired of playing the guessing game with the rate.
Once we booked WDW, I started to get a bit more serious about saving $$$ into the account. The only draw back is I cannot withdraw from that account using my debit card in the States eg get US money in the US. That does not make me happy at all. But maybe that'll change one day.