It's officially official. vSphere 4.1 is going to be the LAST release of ESX. As shown here in the vSphere 4.1 Release Notes:

VMware vSphere 4.1 is the last release for the following product, features, and platforms. VMware will continue to provide technical support for these features and platforms through the end of their support lifecycles.

• VMware ESX. VMware vSphere 4.1 and its subsequent update and patch releases are the last releases to include both ESX and ESXi hypervisor architectures. Future major releases of VMware vSphere will include only the VMware ESXi architecture.
  • VMware recommends that customers start transitioning to the ESXi architecture when deploying VMware vSphere 4.1.
  • VMware will continue to provide technical support for VMware ESX according to the VMware vSphere support policy on the VMware Enterprise Infrastructure Support page.
  • To learn more about the ESXi architecture and how to migrate from ESX to ESXi, go to the VMware ESX to ESXi Upgrade Center.

So it's time for everyone to start the process of migrating to ESXi. There is no other way around it. Get yourself familiar now, or have pity on yourself for the next release. So what if your backup provider or storage provider has plug-ins that have to be installed via the Service Console? It's time to get them on the phone and make sure their dev team is working hard with VMware to have their code built into ESXi. Having the native drivers will put their products on the vSphere 4.1 HCL. I know of too many "cloud backup" providers that have an agent installed on the Service Console. If you're not already a customer, time to start looking at Veeam. Veeam Announces Support for VMware vSphere 4.1

What I don't get is how they link you to the VMware ESX to ESXi Upgrade Center and there is nothing there. Also, don' take this as a real "upgrade" per se, it's more of a side-grade. Digging a bit further and we get to the Upgrade from ESX to ESXi page which shows no real process of "upgrading". So from what I see, the only upgrade is to wipe and fresh install.

Here are a few ways to help you get around keeping your current configuration:

• Use Host Profiles if you have Enterprise+ Licensing - vSphere Host Profile for Dummies
• Check out the vGhettoHostProfile script. only works with ESXi, I'm sure @lamw has more tricks up his sleeve.
• vProfile Configuration Management from Reflex Systems ($)
• Get familiar with Deploying ESXi 4.1 using the Scripted Install feature which can be found on Page 43 of the ESXi Installable and vCenter Server Setup Guide
• Check out Maish's article on Deploy-ESXi v1.0 - My ESXi Script-0-Mania entry - he's been working hard using PowerCLI to script the install.

Can you think of more ways to transport configurations? Let me know!

Read more about my transition at The Migration From ESX to ESXi is Happening. Moving Configurations. Part II