Copying Google Reader UI

If by copying you mean an actual copy, including layout, colors, text, icons etc. that would clearly be a copyright infringement, as well as potential infringement of other intellectual property rights, as well as a potential breach of any applicable acts on fair trade, marketing etc. If by copy you mean producing a UI inspired by or following a similar structure the answer is more likely - but not certain - to be no. In relation to the intellectual property rights related problems it is of no consequence that Google's product is being discontinued, until the rights themselves expire.