Now that I got used to multiple monitors I find it difficult to live without them.
Noah Coad from the Visual Studio Platform posted about future possibilities on multiple monitor support from future Vistual Studio V10. Though this is not the way I use them (I often use one monitor for Outlook, Visual Studio, FeedDemon and another one for Windows Forms / Browser / Applications), this kind of usage can be cool with more than 2 monitors.
But what I really lack is multiple monitor support on Hyper-V (and VMWare Player). May be one of the great advantages of VMWare Workstation 6.