Hi Mark,
In regards to Silverlight 1.0, I cannot personally recommend any, simply because I have not read any of them.
In regards to Silverlight 1.1, it is important to recognize that Silverlight 1.1 has been renamed to Silverlight 2.0. Along this line, I'm excited to announce that I have been working on a book for Silverlight 2.0 since approximately May of 2007. At this point, one chapter is available for free (here). In addition, there is another chapter available to those who pre-order a copy. This additional chapter has been very well received by the readers thus far.
A significant amount of additional content will be released soon after the new version of Silverlight 2.0 is made available at the beginning of March. I am striving for technical accuracy. Because of this, all of the code used in the book will be made available for download to the readers of the book.