I'm not a betting man. However, I'd bet you 25 cents that your users will have a much easier time learning how to use Drupal with the interface I've designed below:
WHY?
This interface is superior to the drupal defaults for a couple key reasons:
1. We can assume that if someone is using your website, they are already familiar, and comfortable with this type of navigation. Nearly every desktop program, from Firefox, to MS Word, to Photoshop, to Explorer, to the Macintosh Finder use this UI pattern. Always seek to design interfaces which your users will already be familiar with.
Today, I spent quite a bit of time wandering drupal's menu system in search of answers. But instead, I uncovered two techniques which made me rethink the questions I was asking. As the latter sentence suggested, I'm a professional writer of fortune cookies on the side (there aren't many of us left...).