I'm still a hobby photographer.
My workflow has changed a bit since I started using Lightroom during the first betas. I like to think of it as personal development.
At import time, I try to use a few keywords that are common for the shoot. I may postpone this step until after import, and mark a bunch of images that I then add keywords to.
I use the colours, stars and pick/reject flags, and still feel like something's missing.
Before, I used to delete duds right away. Just recently, I started flagging them as rejects and deleting them afterwards instead, simply because that means less work.
As I proceed through the body of a shoot, I also try to fit my images into different categories.
For instance, I just returned from a 18 day vacation to continental Europe, in which I used my 20D for vacation snapshots, "oh-that-looks-cool" snapshots, and finally some vain attempts at more serious photography.
I quickly decided on using colour codes to distinguish these categories. Red for pictures with my friends in them, yellow for other possible keepers. These I also add subject specific keywords to.
Images with colours will be reviewed immediately or later for possible image enhancements in the Develop module. If I have concrete ideas on what to do with an image, I try to act on that immediately, unless it's bog standard adjustments.
In these possible keepers categories, I flag as "pick" those that I feel pretty certain that I want to present to someone.
I also use the stars to note that I'm satisfied with an image, and my scale is slightly stricter than Dave Chew's:
1 = Something I'm likely to show to others, which doesn't embarass me (before the criticism, anyway )
2 = I'm reasonably happy.
3 = My expectations are pretty high, I feel that it's a quality image.
I don't know what would merit a 4 or 5.
After enhancing the images as far as I'm willing to go in Lightroom, I may either export directly to a web gallery, or go to Photoshop for further work.