Monthly financial consolidation for large companies? My employer has a rack of servers for one application that are used very heavily for a few days a month then are hardly used for the rest of the time - the databases are currently being moved to internal Fusion-IO devices rather than Fibre Channel SAN drives.
The key consideration there is how many consulting hours will you need to figure out how to build up and tear down whatever Oracle/SAP/etc software that you need to do your financial calculations on the EC2 VM.
You may find that Fusion-IO is cheaper than $50 + 3 months of consulting time.
