The last time I tried the open-source radeon driver it was with an Ati Xpress 1100 chipset. The driver would randomly garble the screen and there was nothing I could do to fix it. Things have perhaps changed but I've never had any issues with Intel.

On Arch, at this time, the X.Org server - as already stated, because the X server is too new - isn't supported yet by the latest AMD proprietary driver.

No, when I buy my next Windows machine it'll have either AMD or nVidia graphics. My current desktop machine, which has AMD graphics, will have those graphics pulled at that time. Which means the machine will then be using its Intel graphics - what is integrated right now on the processor. That machine, the old one when I get my new one, will be Linux. With Intel graphics. And I don't play games under Linux, that's what Windows is for, which will be the new machine - in a year or two.

I'm running a dual-head using XRandR. It works fine. Honestly however I've never used anything more complicated than a dual-screen so I don't want to go off and promise you the moon. Xinerama may be an option for you: before using XRandR I set up with that and even though it's not supposed to compiz did work when in that mode. XRandR, Xinerama, TwinView, you'd think between all that something would work for you.

Ha, nope. Anyone who's been around the Linux block a few times should confirm that Intel graphics drivers (xf86-video-intel) are just the shiznit. Try getting fglrx to run with xorg-server 1.12.1 - what Arch ships - and you'll find that that proprietary driver hasn't been updated to support that version yet. You could always use xf86-video-ati or xf86-video-nouveau but, honestly, both those drivers lack the polish of xf86-video-intel. Intel just works.

Typing this on my Arch laptop, my desktop is Windows..

Intel, with their open-source graphics stack, makes for some of the easiest-to-maintain Linux boxes around. I'm typing this right now on Arch with Intel graphics. Sure, they don't have a lot of "gaming punch" but they are darn stable and just work with Linux.

My desktop right now has Windows and is running a first-generation Core i5 with an AMD Radeon 6870 added in. When that machine get's replaced with another gaming Windows machine in a year or two I'll be pulling the AMD graphics out of it and running on the i5 integrated Intel graphics. It will be super-low-maintenance in Linux. None of this rebuilding fglrx or nVidia modules every time you upgrade the kernel.

When I go looking for a Linux machine the very first thing I look to check-off is "Intel graphics"? Yup, then it's a buy.