If you're going prior to Dec 1, 2007....I'd say Zebra Trail.
The construction going on at AKL right now, to convert 5th and 6th floor rooms to DVC accomodations, will be focused on the lobby area rooms and Giraffe and Ostrich trails until around mid-November (unless they get even further ahead of schedule) with those rooms opening on Dec 1st.
In the interests of being away from the construction (just in case...impact has reportedly been minimal of late), I'd request Zebra Trail, where all the construction is complete and DVC rooms were all open on Sept 1st.