I will be teaching a second Haskell course next semester.  Let's assume that

Introducing functional programming

Getting started with Haskell and GHCi

Basic types and definitions

Designing and writing programs

Data types, tuples and lists

Programming with lists

Defining functions over lists

Playing the game: I/O in Haskell

Reasoning about programs

Generalization: patterns of computation

Higher-order functions

Developing higher-order programs

Overloading, type classes and type checking

Algebraic types

(i.e. the first chapters of Thompson's Haskell: the Craft of Functional Programming book is "beginner, classic Haskell".  The next few chapters, namely

Abstract data types

Lazy programming

Programming with monads

Domain-Specific Languages

Time and space behaviour

would be (re)done at the start of such a second course. The question for cafe is: what else? I will likely cover:
- Typeclassopedia
- finally tagless
- Template Haskell
- Optics
- GADTs
- recursion schemes

I should probably cover parser combinators, pretty-printing, cabal&stack. I know that http://dev.stephendiehl.com/hask/ gives me one heck of a smorgasbord of options, which is kind of a problem.

Things I know I will not cover:
- dependent types (if I was going to do that, I'd switch to Idris/Agda)
- concurrency (don't ask)

Jacques