As far as easily detecting the CGI - I would say there is nothing wrong with your TV, the 360 add-on, or the connection type you are using. People tend to forget that CGI isn't used because it "looks better" - it is used because it is a relatively cheap alternative to creating hard shots or in this case impossible shots (since there are no more T(or V i suppose)Rexs OR giant gorillias. HD-DVD will certainly bring out the detail which may cause things to be a little more fake but that is the nature of adding detail - you notice more things.
Glad to hear the drive worked pretty well. Tis a good day for HD-DVD!