Seems that with Siggraph 2004 coming and going, ATI has finally released the 1.5 version of RenderMonkey. If you are using RM 1.0, i strongly recommend that you upgrade to version 1.5 as it has many more features and is way more stable. For those who have a copy of my book (Shaders for Game Programmers and Artists), you may have noticed that version 1.5 WAS included on the CD-ROM. However, this was the "developer preview version" and there seems to have been some improvements since the release I've included on the CD-ROM (which is about 4 months old).
Here is the list of improvements from version 1.0. I've highlighted in red the features that i think weren't present in the preview version included with my book.
You can find the latest version of RenderMonkey HERE!