This is one thing that I'm very glad Unity does - it removes those menubars and has a global menu like OS X. Saves so much screen space.
I tried the netbook release 10.04 for a week on older hardware; in the end, I felt like I had to jump through another hurdle to get to an application - what I mean is that it was a two step process through the global menu. Dialogues end up a bit messy. It felt half way there - I'm glad though that Ubuntu are at least trying something different.
I removed my top panel by accident in Gnome yesterday, and was thinking about abandoning it, but I placed it back, mainly for the date and time and system resources widget thing - that I like to keep an eye on in case XYZ app gets out of control.
Notification icons are useful, but they should complement proper applications. How do you select wireless networks in Gnome without the wireless icon thing?
I'm one of those that starts to flail if I can't do it on the command line, let alone some system menu.
I abandoned multi-monitors in the end, because I got sick to death of the lack of keyboard control and the unpredictable nature of applications in that environment. Too many assumptions, like me having both monitors turned on. I'd rather think in workspaces, and be able to group apps to a workspace, or shift the menus easily to the one I was using.
I'm sure there are ways around it.
Ultimately I am a command line user overall, so keyboard shortcuts and commands are my bread and butter. I can't remember the last time I really needed the menu bar for something, so even on my dual monitor (laptop, and external screen) MacBook Pro I really don't care where the menu bar is located.