[gordon g]

I use lightroom for almost my entire workflow. When importing, I file by date, which creates separate dated files, and back up the files to a separate location at the same time. (There is an option box for this). I then key word each image.
My key wording system has evolved with use, which is very easy in LR. You can add new sub-categories to a key word, or move an existing key word into another as a subcategory. By using several key words to describe an image, it is easy to give your searches flexibility. (Eg 'flight' may be applied to birds insects and planes in the air, but if I want a picture of a flying bee, then I search for 'flight' and 'insect>bee' together)
I use the colour labels as a marker for how much work I have done on an image. So if it's coded red, then I have done a satisfactory print, yellow means I havent got the final print yet but all the major adjustments are done etc. Star ratings are self-explanatory - I use them to help with the initial sorting into keepers and bins. Following import, I review all the images, star rate them and then sort them according to rating. It is then very simple to select the duds and delete as a batch.
The one thing I might need to start doing now though is batch renaming. Until this summer, my camera was generating unique file names, but I have now clocked it, so I am getting some duplicate file names amongst the keepers. This isnt a problem so far as they are all in their dated files, but if I happen to export two with the same name from LR (which keeps them in their original location) to another application I could end up with confusion.