Others beat me to the punch, such as Pete Bekins and Jay Crisostomo, however, I thought I’d add the links as well. Furthermore, I’d like to thank the Oriental Institute for their electronic initiatives–not only is it a wonderful thing to have these great resources for free it is also very practical to have them in electronic form. Just today I used the electronic version of the L volume of the CAD with my Hebrew class to discuss an Akkadian cognate of a Hebrew word we encountered in the book of Ruth. It’s very impractical for me to lug around all the volumes of the print copy of the CAD but carrying a hard drive around isn’t too bad.
One last note–don’t forget about von Soden’s AHw. Duane Smith has a nice note about this that you should read. While CAD is certainly a monumental achievement and an invaluable resource, it is also well worth the time to check AHw for another opinion.