[CentOS] Virtualisation

I'm building a new server at home to handle most of my internal
requirements (mail, news, dns, dhcp, backups being the biggies).  I also
want it to host a couple of virtual servers which are allowed incoming
connections from the internet (mail gateway, web server, ssh server);
these are virtual so if a hacker _can_ break in then they're limited as
to what they can see.

At present the virtual machines are vserver instances on an old FC2 box.

I'm wondering what people recommend for virtual servers these days?
CentOS 4 with a vserver kernel?  Wait for CentOS 5 and use Xen?  VMware?
(Vmware is the heavy solution, but it does mean I could host a windows
session if I wanted to).  Or Solaris 10 and zones?

Any thoughts?

-- 

rgds
Stephen