For those of us who are never satisfied with our current PDA, I can thoroughly recommend the following sites:
PDAdb.net is Windows Mobile only (no Symbian), but is fantastically comprehensive otherwise. I’ve wasted many hours searching in vain for my perfect PDA.
Steve Litchfield’s 3-Lib hosts a great comparison of all the Series 60 Symbian smartphones. I’d also recommend his Grid comparison (which includes some Windows Mobile devices), and his All About Symbian site for general Symbian news.