Don’t forget about the Survey Tool. It is invaluable when selecting from a number of similar images. Highlight all of the images in the batch and hit N. Use the numbers to rank them by stars and hit / to deselect images and knock them out of your Survey window.
Bonus: New in Lightroom 3, you can hit N from anywhere in Lightroom! Spot Removal has been reassigned to the Q key in the develop module.