I came home tonight and found a copy of Apple Pro Training Series: Aperture 2 sitting on my door step. I'm quite happy with how the book came out (especially since we were able to work in all of the new features in the 2.1 release). The book should start shipping within days... you can order it here. In the mean time (here are some features you won't want to miss).
Customize the Default Adjustment Set
Specify exactly which adjustments you want to appear by default in the Adjustments Inspector/HUD. Two new commands — Add to Default Set and Remove from Default Set — are accessible in the Action pop-up menu for each adjustment in order to configure these settings.
Keyboard support in Adjustment Panels
Make precise image adjustments using the arrow keys on your keyboard to drive the various sliders in the Adjustments Inspector/HUD. To activate keyboard control, click once in the numeric field of an adjustment control (such as Exposure). You can then use the arrow keys to increase or decrease values. Hold down the Option key when using the arrow keys for even more precise adjustment. You can use Tab to move to the next adjustment control (and Shift-Tab to move to a previous control).