I have the Longman Advanced American Dictionary and CD ROM as well, and I dont like carrying it around, too heavy. Now, I can carry the dictionary in my iPhone, v 1.4.1
I would like to see some updates implemented for the iPhone:
1) flip through from word to word. Now, you have to go back and then select the next word in the dictionary. Samething for the favorites list.
2) Implement multiple favorite lists, not only one
3) Be able to see horizontal on the iPhone
4) I would like to be able to record myself pronouncing a word and replay it. (This option is available in the CD but not in the iPhone)
This is a really good dictionary, which includes the pronunciation in IPA and you can listen how to pronounce the words.