I would chose the ArrayList, Vector is part of thw older original collections, and is
thread safty, however, ArrayList is part of the current collection frame work, but isint thread safe, so it is "quicker".
I dont remember much about drop downs, I havent used them in awhile, but if you know what the Timezones are in advance, how many there are of them, and they arent going to change, I wonder if an array of Timezones would not be better?