I use Encoder Pro (the online version so that its always up to date and no waiting for a disc in the mail and have to upgrade myself). I think its awesome and paid extra for the CPT assistant. It is kind of spendy includes EVERYTHING (HCPCS, LCD's, CCI Edits, lay descriptions, modifiers, dx crosscoder, RVU's, instructions, images)
The pitfall: searching for things sometimes can be a bit tricky. There are procedures that I know there are codes for but when I use the search engine it doesnt pull up what I am looking for, thus causing me to break out the good ole reliable book. Over the past few years I've been able to overcome this pitfall due to the experience using it.