One of my favorite books that occupies a permenant place on my nightstand is "Inner Dimensions of Islamic Worship," taken from the Ihya ‘Ulum al-Din by Imam al Ghazzali.
Aside from wanting to read/own all his works, there are a few Imam al Ghazzali related things that are also on my wishlist:
Al-Ghazali: Alchemist of Happiness dvd
Alchemy of Happiness Hamza Yusuf cd set
I've seen a lot of excellent reviews for both around the net.