As of March 29, 2010, it is possible to change the "weight" of a menu item. The weight, combined with alphabetical order, controls the order in which the menu displays.
Lighter vs. Heavier Weights
Although it may seem counter-intuitive, a larger number "sinks" a menu item, making it appear lower in the list and a smaller number "floats" the menu item so it appears higher in the list.
Weights are integer values, and include both positive and negative values. In case it's not obvious: -50 is lighter than 0, which is lighter than 50.
If two items have the same weight, they are listed in alphabetical order.
For example, with weights in parenthesis:
- (-45) Talking Heads
- (-15) The Kinks
- (0) The Beatles
- (2) Hootie
- (2) The Blowfish
- (11) Spinal Tap
- (32) *NSYNC
- (45) Queen
Changing the Weight of a Menu Item
To change the weight of a node's menu item, simply
- Locate the node with the menu item you want to change.
- Go to that node's editing interface.
- Scroll to the bottom of the page.
- Below the "Section Assignment" field, you should see a "Weight" drop down menu.
- Select the desired weight and press Save.
Implications of Changing the Weight
As you change more and more weights of menu items, it becomes increasingly hard to keep track of what items have what weight and where a new item will appear in a menu. Because of this, the Web Guys [initially] recommend that you change as few menu weights as possible.
Best Practices for Changing Weights
When arranging a menu, start by changing the weights for the top and bottom items in the menu. These are often the ones you are most sure of and are often likely to remain in place. Try setting these to -45 (the top) and 45 (the bottom). From there, work your way down the menu, always leaving at least 5 between each menu item so there is space to insert items between currently adjacent items in the future.
Making Major Changes to Menu Order
In many cases, it may still be easier to have a power user assist you in changing menu order if you have more than 5 or 10 items to rearrange or if you want to move several pages to a different parent. Power Users are happy to help and you can find the one nearest you on the Help Section's list of power users.
Remember: Drupal's menu system is pro-family and will never separate parents from their children. That is to say, when you move an item with children, it's children will remain directly beneath them in the menu. In addition, changing a node's location doesn't affect the order of items under it, but the weight you've given the node could affect where that node appears in the new parent's menu.