Really?
I liked Equal Rites more than anything with much of Rincewind.
Off the top of my head Lords & Ladies is my favorite, but reading Wyrd Sisters, and Witches Abroad sets it up (as does Equal Rites to lesser extent), otherwise I thought that
Mort
Guards! Guards!
Men at Arms
Hogfather
The Last Hero
Night Watch
The Wee Free Men
A Hat Full of Sky
Wintersmith,
and
I Shall Wear Midnight
were all standouts in the series.