Caution: Rant Alert
It's an arbitrary and artificial cycle without relation to the natural cycles of the world, an oppressive seven-headed monster.
I say, let's kill it. Death to the week!
Yes, I know that pagans invented it. (Since pagans invented just about everything, that's really no great shakes. Pagans invented slavery and genital mutilation too. Face it, they haven't all been winners.) Tart it up with pagan god-names if you like, but we are not fooled. The intrusive Roman proves it's a foreign import.
When Muhammad of Mecca (piss be upon him) was setting up Islam, he intentionally replaced the traditional solar-lunar calendar with a strictly lunar calendar that careened through the solar year like a drunken bicyclist. In this way he guaranteed that the holidays of his religion would never accrete any of those nasty (and inevitably paganizing) seasonal associations, as the holidays of Judaism and Christianity had. Well, you can't say he wasn't savvy.
Same deal with the week. That's why the Hebrew prophets denounced new moons and holidays and championed the Sabbath instead. Stop looking at the Sun and Moon to tell time; you don't need them. Look at the calendar instead. Why measure our lives by the cycles of nature when we've got this nice, convenient, man-made cycle instead?