This is a great list and a must read for anyone doing WP7 development.

In my opinion, you will always be better off using the bare minimum amount of XAML. XAML is completely unnecessary and is a huge barrier to adoption of WPF/SL. You've been better off avoiding XAML this Since SL2; heck you've been better off since WPF beta. That means no databinding, avoid converters, and do the layouts in C#. I.e., not the way the documentation tells you to do it. In fact, much of the list boils down to the above advice.