1. For anyone involved in plastic injection moulding the monthly "Design Tips e-Newsletter" from Protomold offers some really good tips & tricks, check it out here; http://www.protomold.co.uk/DesignTips.aspx They explain the basic rules to producing a successful plastic parts and clearly explain the differences in resins, surface finishes & shrinkage issues.
2. A good place to seek out some inspiration or perhaps help out fellow designers is the Product Design Forums - http://www.productdesignforums.com/
3. Although they are now mainstream, there is no doubt Apple offer some of the most impressive hardware and software designs in the world. If your a product designer then Apple has to be one of your most respected businesses, pick up any of the latest iPhones or even an iPod 3 or 4 years old and you find no screws, no ugly split lines and no cheap plastic finishes & materials.