My two most vivid memories of my first trip to WDW the year it opened was crashing a Sea Raycer into the dock at the Poly and standing in a line outside the building for the Hall of Presidents. And that really is the longest line I remember.
Times have changed.
For me, it wasn't the Hall of Presidents it was Country Bear Jamboree. The shop to the right of the entrance used to hold queue line for country bears. Our first trip was in 1976, and I also remember my mom deciding I was still too young at 8 year old to ride space mountain. The older 3 got to ride but me and my younger sister didn't.
To the original question, it really depends on the ride and the trip. In general, I would like to have an average wait of under 30 minutes. That being said I wouldn't be above waiting an hour for one of my favorites. But like I said, sometimes the situation dictation something different.
On my last trip I arrive at WDW on Dec 31, 2012 in the middle of the afternoon and by the time I had gotten to EPCOT it was 6:00. The primary goal was to see the NYE fireworks and the special stuff at EPCOT only available on NYE. By the time I had gotten there the only FP's remaining were for living with the land. Soarin and TT had 4 hour waits listed, MS and Maelstrom had 2 hour waits. After eating supper I ended up waiting 30 minutes for figment and 40 minutes for Nemo, along with using a FP for Living with the land. On a normal trip I'd never wait that long for those rides.
I think a large number of people in this thread have a warped view of the typical wait times of a WDW visitor myself included. When you look combine the thread we had that stated that half of guest don't use any FP's with the wait time estimates in Easy WDW cheat sheets
http://www.easywdw.com/category/cheat-sheets/ . The typical WDW guest , especially in the summer, is standing in multiple hour plus long lines.