This is pretty close to how I work. I never tossed any film that I shot and I don't delete off my disk any digital image I shot. I do keep the obvious garbage out of Lightroom, but other than that, they all stay in the catalog.
My scenario is a bit different from some other's here. I am often shooting sports and need to deliver something quickly. So out of my 500-1200 images per game, I'll quickly go through, pick my initial keepers, process and deliver.
When I have slow weekends, I go back through that, and take my time. I often find stuff that was previously ignored, and I often re-classify some of the initial keepers as not that great.
I also find that my idea of a keeper is different from those of my clients. Or rather stuff I won't use is different. Most don't care if an image is slightly soft. It's their kid, or their teammate, or whatever. Now if it's going to print, that's different. But just for prints to go in the family album...its 10x better than they could have gotten with their point and shoot. And they love them. I try to bear that in mind.
The one thing I wish I could do in lightroom but can't is to see the focus points from the camera. I will sometimes pull my RAW images into ViewNX just to see WHY I missed. Or what the camera was doing.