Cloud Computing Platform

So recently my colleague's startup really need a scalable application, that could handle billion hits, so I really need to learn to utilize cloud service instead of depend on one or two normal PC with huge RAM (that I prefer to use when the users are lower than 10k of non-static hit), rather than building your own server farm, that probably costs higher. Some of the famous cloud (IaaS or PaaS) services are:

• Amazon Web Services
• Amazon Elastic Compute Cloud (EC2) - VM on demand
• Amazon Lambda - event runner and compute resource manager
• Amazon Simple Storage Service (S3) - similar to Google Cloud Storage
• Amazon Glacier - archival
• Amazon Elastic MapReduce (EMR)
• Amazon Route 53 - DNS web service
• Amazon Virtual Private Cloud (VPC) - EC2 with VPN
• AWS Direct Connect - dedicated network connection
• Amazon Elastic Load Balancing (ELB)
• Amazon CloudFront, a content delivery network (CDN)
• Amazon DynamoDB - NoSQL
• Amazon ElastiCache - redis and memcache
• Amazon Relational Database Service - MySQL, PostgreSQL, Oracle, SQL Server
• Amazon Redshift - data warehousing
• Amazon SimpleDB - S3 on webservice
• AWS Data Pipeline - migration between storage service
• Amazon Kinesis - streaming
• AWS Elastic Beanstalk - deployment, amazon's GAE-like product
• Amazon CloudWatch - monitoring
• AWS Management Console - cloud management
• Amazon Machine Learning
• Amazon CloudSearch - FTS
• Amazon Elastic Transcoder (ETS) - video transcoding
• Amazon Simple Notification Service (SNS)
• Amazon Simple Workflow (SWF) - background jobs
• Amazon Cognito - secure sync mobile app data
• Amazon AppStream - low latency stream
• Amazon Mechanical Turk (MTurk) - crowdsource small tasks
• Google Cloud Platform
• Google App Engine (GAE) - automatic scaling platform
• Google Compute Engine - VM on demand (equal to Amazon EC2)
• Google Container Engine - docker
• Google Cloud Storage (Google Storage) - RESTful file storage with atomic consistency, ACL, and resumable upload
• Google Cloud Bigtable - NoSQL (beta)
• Google Cloud Datastore - NoSQL with SQL-like query language
• Google Cloud SQL - MySQL 
• Google Load Balancing - balance traffic between compute engine instances
• Google Interconnects - join to Google network
• Google Cloud DNS - managed DNS
• Google BigQuery - map-reduce the Google Cloud Storage 
• Google Dataflow - ETL analytics
• Google Cloud Pub/Sub - async messaging
• Google Cloud Endpoints - rest API for web/js or mobile clients
• Google Translate API 
• Google Prediction API 
• Google Cloud Monitoring 
• Google Cloud Logging 
• Google Cloud Deployment Manager 
• IBM BlueMix (Java, Node.js, Go, PHP, Python, Ruby Sinatra, Ruby on Rails)
• AppScale - GAE clone (like CapeDwarf and TyphoonAE)
• Programming Language: Go, Java, PHP, and Python
• Datastore API: Apache Cassandra and Apache ZooKeeper
• Memcache API: memcached
• Task Queue API: RabbitMQ and Celery Task Queue
• XMPP API: ejabberd
• Channel API: strophe.js and ejabberd
• Blobstore API: Apache Cassandra and Apache ZooKeeper
• Images API: Python Imaging Library (PIL)
• Cron API: Vixie Cron
• vCloud Air (VMWare)
• Force.com (APEX programming language)
• RightScale - IaaS management service
• OrangeScape - cloud application builder under AWS
• openQRM - heterogeneous infrastructure manager
• OpenShift (Red Hat)
• Programming Language: Haskell, Java, JavaScript, .NET, Perl, PHP, Python, Ruby
• Database: Microsoft SQL Server, MongoDB, MySQL, PostgreSQL
• Tsuru - HA, auto-scaling, auto-healing
• Programming Language: Buildpacks, Cordova, Java, Node.js, Go, PyPy, Python, Ruby, PHP, HHVM, Elixir
• Database: MongoDB, MySQL, PostgreSQL, Redis
• Heroku (Ruby, Java, Node.js, Scala, Clojure, Python, PHP and Go)
• Cloud Foundry - layers above AWS
• Data Storage: MySQL, PostgreSQL, MongoDB, Redis, Riak, DataStax (Cassandra), Neo4J, Pivotal HD (Hadoop)
• Messaging: Pivotal RabbitMQ
• Development: CloudBees Jenkins (Continuous Integration)
• Mobile: API Gateway, Data Sync, Push Notifications (Pivotal proprietary services to support Mobile Apps)
• Programming Language: Java, Ruby, Node.js, Scala, Python, PHP, Go
• Engine Yard (Ruby on Rails, PHP and Node.js)
• Jelastic (Java, Node.js, Ruby, Python, .NET/Windows and PHP)

Some parts of the information above shamelessly copied from wikipedia. There are some comparison about the price, more price, even more price, features, terms, and performance out there. Which one the best for you? depends on your budget and your developer's skill.