Something neat to say if you're an evil overlord, villian or otherwise bad guy, usually during the climactic final battle between yourself and the goodie-twoshoes hero.

Besides sounding ominous and overlord-like, it also has biblical connotations, so if you're one of those satanic villians using this quote is an even better idea. The bible has it go something like this:

"And he who sat upon the throne said, "Behold, I make all things new." Also he said, "Write this, for these words are trustworthy and true." And he said to me, "It is done! I am the Alpha and the Omega, the beginning and the end. To the thirsty I will give from the fountain of the water of life without payment. He who conquers shall have this heritage, and I will be his God and he shall be my son. But as for the cowardly, the faithless, the polluted as for murderers, fornicators, sorcerers, idolaters, and all liars, their lot shall be in the lake that burns with fire and sulphur, which is the second death.""
Revelation 21:4-8

Be sure to include that bit about alpha and omega if you intend to go with the biblical overtones.