I 10000% agree with Frank and Lisa! The last time I made an ADR was when EPCOT had the WorldKey Kiasks for video confernces. With the exception of buying a Hoop Dee Doo Revue ticket, WorldKey was the only time my family of 3 or 4 people has ever made an ADR (then known as Priority Seating). I have been told that I have "ADR phobia," but I just have never had a problem walking up.
After seeing people on the boards plan their entire day around a restaurant, I tried an experiment.
In last week of April 2010, I called WDW-DINE from the parks. There would be no availability at the restaurants I asked for. After getting off the phone, I went right up to the podium at said restaurants and got a table for 3 with only a 30-40 minute wait.
If at anytime, my first choice was full.....there are other choices. If I need something fast? Hey.....there is the theme park staple hot dog available. The planet will not explode because I dont have an ADR.

I do enjoy a good meal, but bottom line is that food is food. It will keep me alive til the next meal. I am not gonna give up seeing something that is going on because of food.
Yes, I know..... "But if you have the dining plan...." I use the dining plan alot. My credits have never been declined due to the lack of ADR. The waitstaff swipes my card with no fuss at all.
If ADRs are your thing, then you should do it. They are just a waste of time for me personally. The exception being dinner show tickets and eating before a park opens. Other than that, I personally do not see the point of ADRs. I dont know what I want to eat 6 hours from now, let alone 6 months from now.
Again, this is just my personal experience and personal preference. Please do not write to me to explain the "NEED" for ADRs.
For rides, I can see reserved times for popular attractions, but times would have to be spread out to allow for standbys.