Which Tom Waits CD you recommend?   

I like Small Change the best - it's early enough that it's got some of the straight ahead and some of the experimental - a bit more sentimental than Rain Dogs or Swordfishtrombones, which I also really liked.

depends on your taste. His early work such as Closing Time and Heart of Saturday Night have great traditionally crafted songs on them and for those who aren't fond of his voice it is at its least gravelly. Many say his mid period was his best with Franks Wild Years and Rain Dogs where he began to get a little experimental. Then you have his recent bluesier take on things with Mule Variations and the recent Orphans. The latter would be a good place to start.