We typically take two 16gb SD cards for our camera. That is A LOT of space for pics, even when taken at full capacity.
We've taken anywhere from 50 to 1,500 depending on the circumstance.
I have probably taken more pics (other than food) in the TOT que than any other place when looking back at them. I try a bunch of different techniques on each capture, so that can add up. I say take as many as your SD card can physically hold. Not to mention if you use it for HD video that can use a lot of space. Sometimes you never know what you will end up with.
For example....I will share my BEST Disney picture I have ever taken. I took this picture in 2011 while staking out a spot for the Electric Parade. This was one of our last nights at Disney and I was tired of carrying around the big camera so I stuck our tiny Sony Point and Shoot in my pocket....just in case. I took probably 100 different pics from every angle while we were killing time. When we got home I started sorting through things and found this one. It's totally unedited in any way whatsoever....straight out of the camera. Regardless of what Josh says, sometimes photography isn't a scam and you just get some pixie dust thrown your way.