My hosting provider Bytemark started to develop a new virtual server technology some time ago. It's marginally cheaper and marginally more powerful than my current solution. It has many scalability advantages as well but they are not as important to me as the fact I was due to upgrade my existing server and migrating to a new box has many advantages over an in situ upgrade.
I signed up to their free trial and was instantly impressed by both the technology and their customer support. I know there are other good companies so in no way do I want to criticise them, but Bytemark are very good people to work with.
I built my new Debian box, installed the packages I wanted and ported the bits over from the old server over a few evenings. It took only a few hours, and in the process I was able to improve some of the layout and such of the new box and try out newer packages.
This week I updated the DNS records updating the box names and other than forgetting to switch my email server from listening local to listening to the network everything went very well. All that happened was email was backed-up for a few hours before it all arrived.
I've now stripped the old box down to it's minimal running configuration, deleted all my files, and I'm now filling the filesystem up with random junk before deleting the junk and switching the box off so that it can be returned to Bytemark.