On the MMBug Mailing List, there was mention of a couple of good dropdown menu sources that work on every browser. Here’s where it pays to buy software from someone who’s specialized in a very convoluted field: browser compatibility for tricky DHTML programming. I’m making this entry so I don’t forget, because this is a pretty common thing to need.
Ultimate Dropdown Menu from Brothercake. I like his site, and he’s a good example of a niche software guy that I would do well to emulate: know your stuff, be good at what you do, provide an accessible product, and present yourself well.
Milonic, which I looked into a while ago and ultimately didn’t use.
Coolmenus, which was what I used for one project once, but doesn’t seem to be actively updated any longer. The site is really slow too (I know, I’m one to talk).
David W. 
I’ve been using MenuMachine in GoLive lately and it’s pretty good, and fairly cheap too. It’s not as pretty as UDM or Milonic (no ‘icon’ menus, although perhaps with some custom scripting it would be possible) but it has a useful interface built into the GoLive system.
——-