I love nail polish, (in fact, it's what really got me into makeup) and there are so many option it can almost give you a headache. I think that if you want something that is neutral but a little more exciting than the run of the mill french tip, then try some of the colors by Revlon. I'm not sure if they're still selling these colors, but try Sandstorm (Light beige) or one of the coppers like Platinum Copper Glaze (don't try anything as dark as Amber Ablaze if neutral is the look you're going for). I think that Revlon has some very nice stuff in a wide variety of shade, and if you apply it properly and take care of it, it can last about 5 days.
If you want, always adding a base color will help the color stand out more. For darker browns I generally use black as a base, but for lighter browns, either I add a midtone brown as a base or skip a base all together (like in the case of Sandstorm).
Hope that helps.