Air Canada Aeroplan has some serious advantages if you're aiming for *Gold, but don't fly alot of J or F. As others have mentioned it has the lowest single-year mileage threshold: 35,000. The standard for most Star FF programs is 50,000 miles.

That said, there are some caveats.
First, a key factor for you is that Air Canada does a terrible job of non-* partners... as a matter of fact I don't think they have any major international carrier partner beyond * Alliance. Certainly not Qatar or Virgin.
Second, the mileage accrual period is the calendar year as opposed to the more generous 12-month period on some other airlines.
Third, again as others have mentioned and bluebomber's chart shows, the bonus status miles for flying J or F are limited (25%/50%).

I'll also point out that there are other complaints in the AC forum (and I would concur) about other issues with the Aeroplan programme such as poor IT (bad website) and steadily declining perks that come with top tier status.

In short, in many cases Air Canada can by far be the easiest way to get *gold, but if you know you're going to exceed 40-45k there might be other plans out there which will be better.

Hope it helps!