Ummm, let me think about that for a second..... no.
3 screens is simply an extension of two. Almost everyone can plug in a second monitor to their second video port, then it's just a question of telling XP that there is a second screen and you get an extended desktop - no extra drivers or special software needed.
Since screens are so damn cheap these days there's almost no excuse not to have a second screen.
To add the third screen I had to get a second video card, but that wasn't a drama.
I find it difficult to work with a single screen these days, I don't know how you all manage
The trick is also to choose a TFT with a very thin border - makes life easier. I've also thought of adding more screens (like another row along the top), but it starts to get difficult on the neck.