kvm?

[Neal Becker]

I've been using virtualbox, and it's pretty nice.  I'm wondering if any of the more open virtualization efforts have progressed to the point that I'd want to try replacing virtualbox.  What I'm interested in is:

1) Able to run windoze/linux guest on linux x86_64 host
2) good performance (on modern hardware)
3) Decent gui

Last I checked, #3 was not there.  Virtualbox has a good gui for managing machines.