Really, all I've ever wanted is an IaaS provider that gives me VMs in the shape of Heroku's instance partitions: a little bit of guaranteed CPU/memory/IOPS per dollar, with cheap/free low-jitter bandwidth thrown in, made specifically for allowing network-server applications that scale horizontally.
My 64MB-of-memory IO-bound Erlang chat server doesn't need a 4GB instance with eight cores. But it has to take that instance, because that's what you pay for in order to get a good uplink.