I dislike the look of Droid Serif. I use Droid Sans as my UI font on my netbook (running Ubuntu), though. I'll certainly compare them when the Ubuntu font is released.
Note that font rendering differs massively between distributions. I prefer Ubuntu's softer (OS X -style) look best. Others might prefer Fedora's crisp (Windows-style) rendering.
My main problem with RWH (and I'm not alone in saying this) is that the first 4 chapters are insufficient to prepare you for the material in the rest of the book.
Read "Programming in Haskell" by Graham Hutton first. It's a small book... I literally did the whole thing (including implementing all the exercises) in a week. To call it excellent would be the understatement of the century.
From there, pick up RWH. You can skim the first few chapters, and you'll be much better equipped to read the rest of them.
If you use the operator, it's (hopefully) safe to assume you know what it does. Then you should also know what interleaving the operator between the list elements does. Which is exactly what the reduction does. I don't understand your problem with it.