There are 3 schools of thought about what to call a marketing agency. The first says be practical and call it something that relates to the product that you are selling. Good examples of this include "Ideo" and "Whatif!?" in the innovation space and "mindshare" in the media space. The second is call it something more iconoclastic, abstract and creative like "Elephants can't jump" or "Lucky Generals". the third days call it after a name, whether yours or someone else's. This leads to "Ogilvy & Mather" or "Saatchi and Saatchi". There is no right or wrong way. You need to choose a name that you and your partners can get behind and that will work over a long period of time and as your agency evolves and morphs what it does. The only key point to remember is that a) you should be able to tell a story off it - after all this is what creative people are supposed to do - and b) it is memorable

If you want commitment then set up a proper Limited liability venture. This is just as much about making the business work as it is about structuring for tax reasons