If I am at an event and have some down time, I might review on the LCD and get rid of the obvious duds. I have plenty of battery power, though, so that is not a concern.
Yes, storage is cheap, but time is not. If you ever go back to a shoot and want to find something, it is helpful to have the obvious duds gone. I've got too many where I thought I might use them one day,but I reallize now that it's never gonna happen. I mean, something that I thought might be useful as a texture or something turns out to be something that I can't even remember where I saved it.
I now make a folder for each shoot and then sub-folders for various purposes. For instance, I have one for archive and prints and a different one for editorial submissions under the same shoot. I title the shoot folders with a code for date and a very brief description so I can find it later.
Example: 20110225 Snow Geese
If you put the date in that format, yyyymmdd, the folders will sort in chronological order for you.