> Seven, because seven is the Biblical number of perfection. Anyone who says "6" must be OF THE DEVIL!!! (jk :oP)
>

The perfection, from the New Testament, is three (Father, Son and Holy Spirit).

Following esotherical doctrines, the devil number is '666'; 1800 is Jesus Christ.
In the Middle Ages, the perfect number was 10 (the number of 'celestial spheres' that separated earth from heaven); 3 was the ternary nature of God (Father, Son and Holy Spirit) while 4 was our world (the four elements: earth, water, wind and fire).
As far as Christian religion is concerned, three are also the teologal virtues (hope, charity and faith); four are the cardinal virtues (don't remember the list).
Seven are also the Capital Sins, while eight are the Books in the Old Testament.
Six are the days needed to create the Universe, so 6 is a good number.

The apotheosis of the mystical numbers is the poem from Dante (in Italian, is the "Divina Commedia" - don't know actually how to translate into English). This poem is made of three (=the perfection of God) books (Hell, Purgatory and Heaven), each of which has 33 chapters (3x11, that's 10+1, or the perfection of Universe and the Unity of God), plus an introductory chapter; so 3x33+1 is 100, that's 10x10 (again the perfection of Universe, squared).

Anyway, a reading of "The golden bough, a study in magic and religion" from J.Frazer (Cambridge, 1911) will show that mystical numbers have almost the same meaning in each religion, from prehistoric ones to the tribal folklore in Africa.

AP.