I'm running a triple-monitor setup in my workstation, 3x DVI. And I'd personally like to unload one of the secondary monitors from my GTX275. Right now, I have a GTX275 and an 8400GS installed, using the 3 DVI ports I have.
Call it whatever you like, but I would like to be able to run my secondary 20" monitors on a dedicated secondary card. Just the way I am, lol. The secondary card doesn't need to be crazy powerful, hence the bus-powered requirement... the GTX275 sucks up enough juice already