Virtualization has other benefits besides letting people share some hardware. One of the greatest features available in Xen and OpenVZ (and presumably others too) is the ability to live migrate a guest from one host to another.

On a dedicated machine upgrades normally mean downtime. By putting Xen or OpenVZ in place first, and then using a guest for all your services you gain some flexibility. If you decide you would like another guest for some testing then just resize the main one and create it. If you need to maintain/upgrade the hardware just migrate the guests on to a temporary machine, upgrade, and then migrate them back again. And if you want a really good hot spare just keep a second machine going with synced discs and some monitoring that can bring the guests up moments after the primary node has died.

One of the advantages of going with VPS is that you might be getting all of this as standard, but you would need to check first as you could also be getting a small share of some ropey kit with no redundancy.

If you went the dedicated route you could set all that up by yourself, but on the down side it is a fair chunk of work. Maybe it would be worth talking to a VPS hosting company that has the necessary experience and flexibility to provide you with a custom solution that really meets your needs, since you say financing is not a problem.

Best Regards,

Jim