LXC sounds great, running multiple separated linuxes is a great thing (from a security point of view, and ease of maintenance If you someday discover your mailserver-vm is not working You might run into all kinds of problems AND LIMITATIONS. Yes: limitations, because there are some things that won't run correctly on lxc (yet).
Wikipedia: Comparison of (platform) virtual machines (lxc, KVM, OpenVZ, and many more)
If I find lxc to be unfit/unsuitable for my purpose, I will have a look at KVM (Kernel-based Virtual Machine), though it will require other hardware.. Another site that lists a few of them is the Debian system virtualization portal. /*
Even before starting installing the lxc software, there are some important(?) decisions to make:
/* will lxc use these technologies or is it just for KVM?
todo: links to other sites, full- vs. para-virtualization; kvm vs lxc vs xen vs vmware vs virtualbox */