First time poster. I'm from the valleys and "koom" (short "oo" sound as in book or took) is the closest phonetic rendering of the way I'd pronounce cwm.
Top 5 Discworld:
Thief of Time
Guards! Guards!
Maskerade
Small Gods
Hogfather
I've read less then half the DW world books though.
Yeah, I was thinking about that when I made my list, but since it's more of a parody of "Faust" than it is a typical Rincewind-runs-from-things yarn and since Eric, rather than Rincewind, is the main character I put it into its own sorta hybrid category. Besides, I hated "Eric" so much I thought it deserved its own spot on the list
Oh poo. I forgot Jingo, not sure which one I'd replace for it though. I'm a big fan of Carpe Jugulum and Reaperman too, choosing favourites really is difficult.