Was about to comment on that part you just edited out, Cookie... the reason I (and I bet most other) use Ultramon is to extend the taskbar to the second monitor. If you know another (freeware
application that does it, then I'd be
very interested in it (I know there is one but it doesn't have the proper Vista skin in the free version and it also for some reason wants to add stuff like the clock to the second taskbar).
When it comes to Synergy, it's an application to share one keyboard and mouse between many computers (essentially making the second computer act like another monitor for the first one, without being able to move applications between computers).