My name is Chris and I have a problem. I rarely delete photos. But, let me defend myself. Why delete? I'll use this gallery as an example:
http://chrisgohlke.smugmug.com/gallery/1193571
Some of the pictures are completely horrible and should be deleted because they don't add anything to the story to the viewer(they do get better on the later pages of the gallery). But, to my wife and I, this was a once in a lifetime opportunity, so I figured keep everything. When my wife and I look at pictures, even if it is a bad picture, there might be a subtle detail that brings back a laugh or an additional memory that none of the other photos might.
I found this same issue with our wedding photos. A few years after our wedding, I purchased the complete set of negatives from the photographer and had prints made of everything. Even though some of the additional pictures were not very good (which is why he left them out from our original set), there were little details in these that were not in the others which again served to key additional memories of the event.
So, since storage is essentially free, why not keep everything. Sure, if you are putting an album together, hand pick the best. And yes, I do plan on doing just that in my smugmug account, right now I am in the process of loading everything, but I will go back eventually and make the full galleries private and then make a highlights gallery of just the good stuff. Of course then people might think I am a better photographer than I acutally am.