Grats on new books and, of course, nice quote! I read carpe jugulum not too long ago (for the nth time), so it's fresh in memory
From the ones you got there, I think Men At Arms and Jingo are my favourites. Read Guards! Guards! before any of those two though! All the others are safe to start on. Only You Can Save Mankind is of course not Discworld but the first book in the Johnny Maxwell trilogy. Be warned that if you do start on The Color of Magic, the ending will leave you hanging .. it's the only Discworld book to have a truly continous story that goes on into the next book (well, there's Eric too, but). The next book is The Light Fantastic.
Wyrd sisters is the first real witches book (featuring Magrat, Nanny Ogg and Granny Weatherwax) and Pyramids is one of those stand-alone one-book stories and that one is about Pteppic, the prince from the egyptian inspired country Djelybeibi (something along those lines).
If you want a recommendation for another non-Discworld Terry Pratchett book, I'll recommend Good Omens co-written with Neil Gaiman .. It's got a Gaiman-esque cheesy religio-goth plot with the coming of antichrist and various people trying to prevent the apocalypse from happening, among them an angel and a demon, a witch and some witchhunters. Of course it's got that witty Terry Pratchett writing style. Great fun!