[Zarahemna]

I think you are too right, 'best' is so subjective that it can't be boiled down to a couple of sample lists. The real fun of LO is trawling through the forums related to the army of your choice and learning about the range of techniques that other players use when they build army lists.

Space Marines are really quite straightforward, with the more complex armies your chances of producing a near-definitive basic list are virtually non-existent.