Over on VirtualizationAdmin.com, David Davis has an article on why ESXi is the best choice for SMBs, providing ten reasons for this view. Here is the summary:
VMware ESXi is Free
Easy Upgrade to VMware vSphere
Higher consolidation ratio
Memory Over Commitment and Transparent Page Sharing
Most number of complementary applications that you can upgrade to in the future
Choose the right virtualization platform the first time
The most “grassroots” support and education options available
Less Infrastructure and Reduced Energy Costs
Ease of Administration with Snapshot, Cloning, and other Features
“Do More with Less” and “Save Time and Money”
I think it's worth emphasizing points 1 and 2. With ESXi you can get started for free with one (or more…) standalone server, which on today's hardware can easily let you run many VMs (especially when you take advantage of point 4), and then when you want to take advantage of additional features, you can simply upgrade to vSphere without greatly disrupting what you already have built up. Also, points 5 and 7 are as a result of the maturity and widespread adoption of the VMware platform.
