In dozens of client conversations, I keep encountering companies — both IT buyers and vendors — who seem to believe that Amazon’s EC2 platform is the be-all and end-all of the state of the art in cloud computing today. In short, they believe that if you can’t get it on EC2, there’s no cloud platform that can offer it to you. (I saw a blog post recently called “Why, right now, is Amazon the only game in town?” that exemplifies this stance.)

For better or for worse, this is simply not the case. While Amazon’s EC2 platform (and the rest of AWS) is a fantastic technical achievement, and it has demonstrated that it scales well and has a vast amount of spare capacity to be used on demand, as it stands, it’s got some showstoppers for many mainstream adopters. But that doesn’t mean that the rest of the market can’t fill those needs, like:

• Not having to make any changes to applications.
• Non-public-Internet connectivity options.
• High-performance, reliable storage with managed off-site backups.
• Hybridization with dedicated or colocated equipment.
• Meeting compliance and audit requirements.
• Real-time visibility into usage and billing.
• Enterprise-class customer support and managed services.

There are tons of providers who would be happy to sell some or all of that to you — newer names to most people, like GoGrid and SoftLayer, as well as familiar enterprise hosting names like AT&T, Savvis, and Terremark. Even your ostensibly stodgy IT outsourcers are starting to get into this game, although the boundaries of what’s a public cloud service and what’s an outsourced private one start to get blurry.

If you’ve got to suddenly turn up four thousand servers to handle a flash crowd, you’re going to need Amazon. But if you’re like most mainstream businesses looking at cloud today, you’ve got a cash crunch you’ve got to get through, you’re deploying at most dozens of servers this year, and you’re not putting up and tearing down servers hour by hour. Don’t get fooled into thinking that Amazon’s the only possible option for you. It’s just one of many. Every cloud infrastructure services platform is better for some needs than others.

(Gartner clients interested in learning more about Amazon’s EC2 platform should read my note “Is Amazon EC2 Right For You?“. Those wanting to know more about S3 should read “A Look at Amazon’s S3 Cloud-Computing Storage Service“, authored by my colleagues Stan Zaffos and Ray Paquet.)