Macbeth: Was he a bad person?

Allow me to focus on the titular character of the tragedy MacBeth, by William Shakespeare of Statford-Upon-Avon, and his moral standing and personal character. MacBeth, Thane of Glamis, is a commander in the Scottish army, and the receiver of a prophecy from three Witches: MacBeth is destined to be King. Now, by a medieval view, Kings are divinely chosen, mandated by God. Would this not show the rich character of the man? However, power corrupts. To be chosen to be King, as a man is still on the throne, is a tremendous rush of potential power. The potential for power is a huge driving force, and Macbeth responds with thoughts of killing Duncan. However, bad thoughts don't make bad people (thoughtcrimes, anyone?), bad actions do. Unfortunately, this is a far as my English class has read, so I cannot elaborate upon the actions of MacBeth.

To Be a Monarch in the Renaissance

To be a great monarch

It seems to me

Is lesser than purveyors

of soliloquy.

Fancy dress and great food

A comfort no doubt

but the immorality of wealth at waste

puts such comfort right out.

But with such power, I will not lie

Great dreams may I see then

Rather I would be weak than tithe

to masquerading holy men.

Ever right and never wrong
no man could live a way
to claim power from divine
as a need to, in power, stay.

Responsibility, to keep and maintain
a line of blood and sons
To train them up for your same life
with their freedom little to none.

In fear every day, of my own heirs
Poison and blade and bow
Status and power ever attract
Drastic measures and tactics low.

Yes, to be a great monarch
seems lesser to me
than to be a small author
of poetry.