[okey]

Saruman did what he thought best, initially for noble reasons... and that turned out poorly.

This is part of the seductive power theme in LotR, which in general I consider something of a counterpoint to GGP's complaints about "simplistic morals" and "obvious dichotomy".

[wosos]

True, it's an interesting point.

As it was with Boromir (who wanted it for good) or Gandalf when he denies taking the ring. They could've ended doing evil with initial noble intentions, that's how the ring would've exploited them.

[okey]

Exactly. Galadriel, Elrond, and Faramir also have the opportunity to take the One Ring, and choose not to. Sadly Faramir's rejection of it was not portrayed in the movies.