Might be a good idea. I think the general opinion is that it's only going to get worse for awhile.
The financial forecast is for the dollar to continue dropping for the next 1-2 years, hitting $0.70 or so. I would suspect lower.
That's certainly the popular opinion right now. And I don't necessarily disagree - I just paid off a summer cruise myself, and bought a wad of US cash for both the cruise and an upcoming March Orlando trip, because I think the risk of another big drop in that timeframe is much greater than the likelihood of a significant recovery.
BUT... currency markets are notoriously volatile and unpredictable. Economists look at the CAD dropping and say "Oh look, the dollar is dropping, we think it's going to go to X cents". When it nears, reaches, or sometimes surpasses X, they'll look again and say, "Hey, the dollar is still dropping. Now we think it might go as far as Y." Rarely will anyone predict a recovery - except maybe in the vaguest possible terms - until after it's already started to happen. Then it's more of the same ("oh, look at the dollar rising, we think it's going to go up to Z"). Repeat.
So for me, if my timeframe was a year or more, or even 6+ months, whether to pay off an entire vacation at current rates would be a much harder call. I don't think it's likely that we'll see the CAD at par with the USD in the foreseeable future, but a recovery into the mid-eighties is, IMO, entirely possible. Maybe not likely, but certainly possible. Any number of things could trigger it: a change in OPEC's position, some geopolitical shock, better-than-expected performance in the Canadian economy (maybe due to a combination of the recent interest rate cut, the low CAD, and demand in the US), or even just stabilizing oil prices due to changes in production and increased consumer demand (consider the Canadians who will decide to drive south this year to save money, or the SUV-loving population who will decide to drive more just because pump prices are low).
Of course I'm not an economist, and this should NOT be read as a prediction that the CAD is going to rise. It's nothing of the sort. Only a caution against the assumption that economists' predictions on currency movements are a foregone conclusion.