Cozying up to both OSes

A few months ago, I added a second monitor on my PC workstation and I grew to love it. I could keep development applications on the larger screen, and keep email and IM on the other. It was more organized and I could work more efficiently, sliding from one monitor to the other as needed. More recently, I've added my powerbook to my desk, and thanks to various specialized applications, I'm using that as well, but with three monitors spanning two operating systems, I'm finding it cumbersome to jump from one machine to the other regularly.

For a solution, I've been looking into KVM switches like this one. It would let me run my single USB keyboard and mouse on either the mac or PC, and I could switch operating systems on my main monitor with a click of a button. But using dual monitors has made me wish for something more integrated.

My ideal workspace would still span two monitors, and I would still get to use a single keyboard and mouse, but I would love to be able to slide between operating systems fluidly with the same dual monitor desktop setup. This would let me do development work in Photoshop and Homesite on my PC showing in one monitor, and my mac would be running in the second one, running Apache, Mail, and iChat. I could copy URLs from iChat and paste them into my PC running mozilla. Mac on the left screen, PC on the right screen, with a single mouse pointer controlling both and sliding effortlessly between the two; basically the best of both worlds, in a single desktop environment.

While my ideal vision seems impossible on the surface, I can't help but wonder if the best selling PC software emulator for the mac being bought by Microsoft would make this a real-world possibility. While I guess I could get a dual monitor mac setup, with virtual PC running in one full window, I don't want to be tied down to expensive mac hardware that ultimately runs PC apps slow as molasses. On the other hand, perhaps a full screen VNC session with the mac from my PC would accomplish the same thing, and let me stay on the cheaper hardware.

While Apple and Microsoft would likely never want to co-exist on the same desktop, as a computer professional I would love to be in the position of being able to run the best tool for the particular job at hand.

update: thanks to input from various readers, this has been solved!