taffleee, as far as I can remember I read them in order (sadly I am old enough to have read most of them as TP wrote them!)
But while I thought The Colour of Magic was great at the time,the later books are just so much more. At the mo DS and I are reading them,and I won't suggest the early ones til we are stuck for what to read next. We have read a random assortment -Guards,Guards,the first two witches books,Interesting Times,Soul Music,Pyramids,The Lost Continent...if I asked him he would say read The Lost Continent!
Sorry,bit of a diversion from the thread there.
Loved The Various and sequels,and I've not met anyone who has read them in RL.
I've found the books made an impact on me on the lonely dark trudge and solitary wrestling haven't always been classics or great books in themselves,but just had something relevant when I read them,so it is hard to choose books everyone should read.