just make sure you play P&B at the right tempo.
The Goldenberg book is the best tho.. realy good stuff in there. If i had a keyboard around, I'd get my old book out.
2-mallet is ok, but 4-mallet would be more impressive. Try '2 Mexican Dances' its repetitive, and exercises good intependance.
If you want an idea for other 2-mallet pieces, try picking a Motzart, Bach, or Chopin sonata for a wind instrament. Those work well, too.