forward.
after 23 came "penny sparkle" which continued the use of more electronic elements and lush soundscapes, rather than harsh guitars and dissonance.
i love everything this band has done, and i've always felt they belong on vinyl (not a snob, but they really do sound fantastic...and i've never bought one of their albums on CD). if you want to expand your palette, go backwards in order from 23: misery is a butterfly, melody of certain damaged lemons, in an expression of the inexpressible, fake can be just as good, la mia vita violenta, blonde redhead (s/t). that way you'll ease into the louder/crazier stuff.
also, if you get a chance to see them live, do it. i've seen them four times and they've been incredible each time.