My research has led me to a somewhat exotic area: 3-D product shape trademarks. These are rare but powerful forms of intellectual property. They are usually reserved for product shape designs that have iconic characteristics. Their rarity suggests that the average company does not typically invest as much in product design as they should.
Here are some famous shape trademarks I have come across over the years.
Which one is your favorite? (Mine is the fish-shaped cracker)
Note: The product image is followed by the issued trademark.
professororozco.com 
I like the goldfish too, of course, but my favorite is the ever-groovy lava lamp!
Has to be the “Coke” brand bottle.
They’re all iconic, but my vote goes to the VW Bug for probably having the most impact on baby boomers like myself.
Gene,
That’s interesting. Can you tell me more about the nature of the impact the VW Beetle design had on you and your generation?
This is an extremely interesting subject. On one hand, there is an increasing number of trademark registrations for the shapes of bottles and other packages, on the other hand, the European Trademarks and Designs Office and other Trademark Offices (such as in Mexico and Israel) have been rejecting trademark applications for the distinctive shape of objects, such as tools, machines and food.
On the other hand, there is the question to whether its is valid to register as a trademark the three dimensional shape of an object that is also protected by an industrial design patent or registration, valid or expired, given the conflict with public domain.
Arturo, thanks for the insights. As far as I can tell, in the U.S. there is no barrier to getting a shape trademark and a design patent, so long as functionality is not a barrier. Apple received several design patents in addition to the shape trademark for the iPod.
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