Because I work in a large Enterprise environment all the time, it's sometimes easy to forget that the kind of heavyweight infrastructure I'm used to isn't something that most people can afford to operate. In fact, the cost of application stacks like those offered by Oracle, IBM or Sun (with "honorable mention" to SAP and others), goes way beyond the license fees charged. Deploying and maintaining those environments also requires a significant investment in time and human resources that is not only beyond the means of most small to mid-sized businesses, but would actually overwhelm them and distract them from whatever their actual business mission is.
From my limited knowledge of what's actually out there, I see two basic options for "the rest of us", companies and firms that aren't on the Fortune 500 list. Microsoft, or open source. Microsoft's cost to benefit numbers are actually pretty good for small scale deployments. Their technology stack is also mostly complete. Here in America they already "own" the desktop, and so building out using their server products makes alot of sense for many businesses. Of course the problem with Microsoft is that basing your infrastructure on their stack will ultimately result in their "owning" you.
Until a few years ago open source couldn't compete with Microsoft because there weren't any vendors who could deliver an integrated application stack to serve the various requirements of this class of businesses. While IBM, in particular, eagerly integrated open source software like Linux and Apache into their solutions, the cost for both licensing and human resources to deploy and maintain kept them outside the reach of most small and mid-sized businesses.
I think Red Hat changed things dramatically with their acquisition of JBoss and improvements to their operating system (as well as accompanying software) in recent years. Red Hat could be doing more in the area of helping small business, especially, learn how to use technology more effectively than the Microsoft Windows/Office paradigm that that's been dominant for the last two decades. Red Hat has been gaining lately, however, by branding solutions that they've developed with partners to serve different business segments like the Red Hat Enterprise Health Care Platform.
What interests me about the Red Hat stack as it exists today is that so much of it is under-the-covers pure open source that's available elsewhere. The thing that makes Red Hat's distribution of this stuff different is their engineering improvements, particularly in the area of manageability. For example, open source kerberos gets high marks as a proven authentication framework that is notoriously difficult to implement and integrate with the rest of an infrastructure. Red Hat's "re-spin" of kerberos in it's Enterprise Linux product includes integration points with common services like the Apache HTTP server and the OpenLDAP directory. With what Red Hat gives me in a few basic Enterprise Linux subscriptions I can now build an entire infrastructure that works as well if not better than what you can get from any of the vendors who are focused on Enterprise sales at a fraction of the cost -- and I can do it without the proprietary "lock-in" that would result from using Microsoft.
Don't even get me started on the galaxy of Perl and PHP modules that are available as rpms, and how well integrated these are with Red Hat's Apache and MySQL (now finally at v5 after an excruciating number of years stuck in v3) builds.
Although I continue to believe that the price points for Red Hat subscriptions need adjustment in a downward direction, I recognize that this is an easy opinion for someone to have who isn't trying to keep up with the exponential increase in the demand for their services that Red Hat faces. Hopefully they will be able to properly balance profits with reinvestment so that the ultimate cost of a subscription will continue to reflect the real value provided to their customers.