need help on object/rendering structures for 3d engine

I am curious as to how to implement 3d objects in the rendering pipeline for a 3d engine. How I think it works is this. Everything in the world is represented by an object. The object contains the position of each vertex and it''s normal as well as u,v coords and texture info. All the objects are contained in a linked list. Now when I transform the objects from model space to word space i just go through the linked list of objects and transform, rotate, etc. What I don''t know is how the vertex info is stored in the object. Should it be contained in an array or in a vertex buffer and index buffer? I hear of vb/ib all the time and how fast they are. When is a good time to use them? Should I use them at the object level or after in say a render list. Thanks in advance to everyone for their input. Furious George