For the past couple years I've been using a multiple monitor taskbar tool called Actual Multiple Monitors (http://www.actualtools.com/multiplemonitors/) which I think is superior to the tools he recommends (at least it was at the time I tried the others). It allows you to have a fully functional taskbar on every monitor (start menu, notifications area, aero preview, the whole 9 yards).
After becoming accustomed to this tool, I'm convinced this is the right answer for how an OS should do multiple monitors, and I find Windows 7's out of the box support for multiple monitors offensively bad.
All OS's support multiple monitors offensively badly.
The least bad used to be linux with Gnome, which had a bad default configuration but could be quickly configured to work great (without installing additional software even). Of course both Unity and Gnome 3 screwed that up.
Overall I think multiple monitor support isn't on most software developer's radar. Have you seen the full-screen mode in the latest OS X? That's not even bad design, it's absence of design.
On KDE 4.7 (or 4.5+, but there's no reason to use older versions) multiple monitors work exactly how I want them to. It's great.
The only issue is that there is no shortcut for moving windows from screen to screen by default; however, you can set it to be whatever you want from the settings so it isn't much of an issue.
And, unlike OS X, KDE actually has a great full screen mode. I've found that having a fullscreen browser (or two side-by-side) on one monitor and a full screen Emacs on the other is my perfect layout.
Apologies, when I said "all" I wasn't thinking of KDE which is actually the only major DE I've never used in a multi-monitor setup.
From what you say I should probably try it.
> The least bad used to be linux with Gnome, which had a bad default configuration but could be quickly configured to work great
I had a pretty unpleasant experience getting multiple monitors to work properly with Gnome. It's been so long I couldn't tell you exactly what the issue was, though.
In contrast, multi-monitors 'just work' on both Windows and OSX, so I wouldn't say they support it "offensively badly".
I like to think it still is. I'm running Ubuntu 10.04 with Gnome 2.32 on my personal laptop. I'll switch to Arch when Ubuntu ceases support for 10.04, because Gnome 2 seems much saner than unity or gnome 3, at least for now.
After becoming accustomed to this tool, I'm convinced this is the right answer for how an OS should do multiple monitors, and I find Windows 7's out of the box support for multiple monitors offensively bad.