automatic texture coordinate generation

I have searched the forum for such topic but wasn't lucky. I would like to discuss this topic in a non-api way. I know Opengl has GlTexGen, but it's effect is not pleasing (at least to me). I am talking about having an object of any shape, and a texture, then the object will be assigned some good texture coordinates that will wrap or let me say make the texture seems covering the whole area of the object without wrapping or repeating. The OGL sphere map does something like that but it is eye linear, I wrote my own similar function, but the problem with such a sphere map is some not-so-correct mapping on faces lying on the upper and lower faces of a cube. Some would tell me use cube map if the object is a cube, but I am looking for something general, I do not know the shape of the object. I also tried cylinder mapping which also gave me the same kind of distortion. If there such an algorithm, I would really appreciate some notes,books or info about it.