Complaint - skip if you'd like
First, just let me complain about nVidia a bit.

I've got a 256 MB (dedicated) card in my box. Their literature/marketing 'talks' the talk about multiple monitors. Only, in nVidia land multiple equals 2. Oh, you could use 2 Analog CRTs, or 2 analog or digital LCDs - or (sitting down?) ANY COMBINATION of those two.  Heck, throw in support for digital CRTs... and it's party time.

As long as your definition of multiple equals 2. (No way in hell to plug in a third monitor. Stupid bleeps...)

Now for Something Usefull
Another issue I've had, all along, with my nVidia drivers over the years unfolds like this:
1) Mikeey visits website with a funny video.
2) Mikeey has second monitor plugged in.
3) Video launches in tiny box/player on primary monitor.
4) Second monitor flickers... all of a sudden, it's now playinig video - but all stretched-out, gain-y, and at full resolution.

Same thing happened if I watched movies in QuickTime and a host of other things. The pisser though is that it wasn't 100% of the time - just most of the time.

Well, last week I did a lot of work with Camtasia - and it too has a video editor. Meaning that my second monitor was nothing more than a frickin' LOUSY repeat of the player from my first monitor.

Lame.

Complaining to my buddy Carson about this, he said: "I have no idea what you're talking about - I've NEVER seen that happen." Carson has an ATI video card. So I googled on nVidia and dual monitor evil and other terms. I finally got a hit - and a comment on a blog post where somebody complaining about this totally solved my problem.

Turns out nVidia thinks your computer is an APPLIANCE - for watching MOVIES. So anytime the video card detects video - it 'syncs' it on to your second monitor (i mean on to your MULTIPLE monitor) because it knows you want to PARTY.

Anywho... I made the changes listed on that site - worked like a CHARM.