On the published order.
Yes, Small Gods essentially stands alone as a novel, by which I mean there isn't any other novel set in Omnia. That said, there are post-Brutha Omnians in some later novels, particularly Feet Of Clay and Carpe Jugulum.
I found that if you had only ever read them in essentially random order, it is definitely worthwhile re-reading them all in published order. It turns out that a not insignificant amount of humour makes rather more sense the first time you do that (not that PTerry really planned that...).
Wade.
