I believe IaaS will be more ncfebieial. Reason SaaS will have too much competition and competition brings lower prices for consumers, while IaaS under current trends of reducing OPEX/CAPEX as (power/space/servers) from SMB to even larger enterprises would really consider twice rather buying a HW or provisioning IT resources from a hybrid cloud offerings to host their applications/data for a certain duration. For companies as IBM, HP, Cisco and Dell may start offering their independent and stable cloud solutions directly from their own Data centers located globally for IaaS offerings.