Long time Drupal front-end dev but doing more site building lately and have been using Drush much more. One of the biggest limitations I've found with downloading (dl) command is that you have to know the machine name of the module, which is not a big issue for say Views or Context. But who knows the machine name of stuff like node reference or simple google maps?
I guess and get it right sometimes, or I have to hit d.o to figure it out. Is there a list function I havent uncovered? The other answers to this on Stack Overflow and Drupal Answers are pretty bad.
drush dl module-name-here