Hi Mark,
The 'onsite vs offsite' question is one that arises quite often and there really isn't a right answer. I think it comes down to a number of factors and the importance people give to those factors. For example, if money is a factor, then obviously offsite is more attractive. If you have small kids who need an afternoon break, then staying onsite might be better as it cuts down on the time spent going back and forth from the hotel to the parks.
We have done both. Sometimes the whole trip is offsite, sometimes we will spend 1 week onsite and 1 week off, and some trips we stay onsite only. Our last few trip have been onsite only. Everyone one has a different opinion, but both my wife and I feel that when you have to leave the WDW property each day, it is just not the same. You seem to lose the 'magical' feeling. Another plus for us (kids are just about 6 and 4.5), is that our kids love all the things there are to do in Fort Wilderness, which is where we usually stay. With kids the ages ours are, we can't do parks everyday, so we generally operate on an every other day schedule. On the days we don't go to the parks, there are many, many other things to do. I don't think a lot of people realize how much there is in WDW outside of the parks. We have stayed onsite before and not even gone into the parks until we moved offsite.
To answer your questions, early entry was nice when the parks where really busy, but that benefit alone wouldn't sway me one way or the other. As I mentioned before, we feel there are a lot more benefits to staying onsite other than just the EE.
You didn't mention when you were going, but there are some deals to be found at Disney. My parents are staying at the All Stars right now for $49 / night. I think there is another Canadian deal for $59 at the All Stars. If you buy an annual pass, you may be able to get a 30% discount on your reservations. AAA/CAA offers a 10% discount. Go to
www.mousesavers.com to see if there is anything for your travel time. I would guess that the shuttles to the offsite hotels will be slower than the Disney transportation. I think most of the offsite shuttles usually run about once per hour.
I've read many discussions about this topic and as I mentioned I have done both. I think the general concensus usually is, if you can afford it, then stay onsite. There will be people that say that staying onsite is the only way... but they probably don't have to deal with the poor Canadian dollar. There are others who will say that they would never stay onsite. Like I mentioned before, everyone has their own opinion about it. I fall into the category that if I can afford it, I will stay onsite. If not, then I will stay offsite. I would much rather stay offsite in Florida than stay at home in the snow and cold!

I'm sure you will be getting a lot of views on this one. Have fun.
Jeff