I love logos which cleverly utilise negative space. LogoLounge do a superb job in collating logo ideas and inspiration, and also spotting annual trends. I picked up a 2nd hand copy of their LogoLounge 2, which is a bit out of date but still a useful resource for some classic designs.
This logo ticks all the boxes for me, so I wanted to learn more about it by trying to recreate it. The design firm was Eskil Ohisson Inc for the client T Rowe Price. I particularly like how the eye on one side is treated in reverse on the other, giving really beautiful balance and interest.
The technique I used was drawing an outline, forming the shapes to cut out of the main body by using Pen tool, Blend tool for the horns, the Pencil and Pen for the facial features.