vonBaloney: True. I mostly delete the clearly out of focus shots and keep the always there shots. I may rate these almost there shots or mark them for deletion in Lightroom. I'd rather keep one too many photos than delete too much.
reeftool: I have one particular photo printed in 15x10cm. It's small, but still. I've mostly looked at it on the monitor and although I like it, I didn't feel it was "there" when it comes to technicalities. I looked at the photo after a while and was a bit stunned how well it looked on photopaper - and this just adds to the complexity of rating well.
This photo - as said, it's not *bad*, but if you enlarge it, some horrible lens characteristics will show.
This, along with my new profile pic are some of the few photos that really made me think twice about how I rate. I did more self-portraits and my previous favorite was very similar but with better. Both from flash and a nice touch of ambient as well. But I didn't like it when I chose it as my avatar on various sites. Had a look at all of exposures again using the exclude-all-bad-ones-first technique and landed with this new one, and now I also have a much much better feeling about it.
I've read mood can affect how you rate and this doesn't surprise me. Mood has been affecting my music and movies taste for a long time so why not images - I'd just like a better method of rating so I can avoid or reduce the number of times I keep finding new favorites.