With KVM... "modprobe kvm-intel" (or -amd or whatever) That will work on any recent Linux distribution. The difference being is that KVM is already there. Having to install a modified qemu is all I need to do and is _still_ quite a bit simplier and less problem prone then what you pasted there.
With my laptop, for example, which I make heavy use of virtualization for small development and documentation projects I run Fedora 10 for various reasons (my prefered distribution is Debian, btw). I have a Intel GMA X3100 video card and wifi. For various other reasons I like to have DRI2 enabled. This requires having a rather new kernel, a very new kernel (along with newer X stuff)
Also I like having good power management stuff. Being able to suspend my laptop and such is very handy as I move around quite a bit.
All of this sort of stuff makes life for a Xen user much much more difficult.
Also all the benefits of running Xen seem to stem from it's paravirtualization features. For what I do I need full virtualization... Having to muck around with the kernel of the guest systems in addition to the kernel of the host system is just not worth the trouble and is frequently not really even practical.