I prefer very simple designs that can be replicated predictably and inexpensively across a range of media. Try getting a complicated logo with shines, etc. on a pen or a hat. Yikes! The design with radiating circles is based on Gurus usually being depicted on top of a mountain with rays of wisdom coming from their head. See the mountain in the negative space of the circles? The next is just a simple form. Each use a type face that is rounded so the mark and the type are integrated.