It isn't even all that slow in-game. Sure, the mouse pointer is a bit heavier, but this is a netbook. On a high-end system it could handily be an option. (Not that we shouldn't try to optimize it anyway, of course.)
One thing I like in Spahbod's setup is that you can click around freely in the map list to explore the various maps, whereas in a dropdown list you would constantly have to go up and click that little annoying dropdown-arrow button, making the list effectively impossible to explore.