Currently the notification email of a new user awaiting approval is that same as the default registration email, which is easily ignored in my case. Additionally the "approve new user" page is buried under the "Users" menu, and with not badge or any visual indication that there is a user awaiting approval. Because of these two things it makes it very easy for me to leave a potential user waiting for approval for a while.
I've already requested an easier way (than hacking core files) to customize the admin notification email. But I also wanted to request some type of count badge (like you get with updates or comment) to be added the Users menu. Maybe there is a better solution, but that's my first thought.