I used to use Slicehost, but moved to Linode once they launched their backup service. The admin UI isn't as pretty, but IMO the service is better (and they have

I used to use Slicehost, but moved to Linode once they launched their backup service. The admin UI isn't as pretty, but IMO the service is better (and they have VPS hosts in London, which shaves a few milliseconds off for me). At Fantastic, we recently moved from Slicehost to The Rackspace Cloud. We're pretty impressed with them so far.