I have (ESXi 4.1 U1) according to the Update Manger in vCenter Server system. We are entitled to: vCenter Server Standard, vCenter Site Recovery Manager, vSphere Enterprise Plus and I know we have license for newer products..
1) VMWare Product Interoperability Matrixes/Solution Upgrade Path shows ESXi 4.1 U1 to ESXi 5.0 U2 as an in-place upgrade. If I can get to that point maybe I can do this so called "in-place upgrade" to another version level up until I'm current. I need this dummy downed way because I have no clue whats needed to download and do this. Seems there is a Standard or Enterprise download, then you deal with storage drivers the hole big bang. I'm logged into my account and can't locate a vSphere 5.0 U2 download. I have a support ticket opened but I'm not sure how deep my support level is with VMWare. How do I start and make it work without getting overwhelmed and side tracked?
The first thing you probably want to check, if you're running 4.1 U1, is if the hardware you're running on is compatible with the newer versions of ESXi.
After check the hardware compatibility, if your ESXi host is managed by vCenter and if this vCenter is running on version 4.1 too, you will need first upgrade the vCenter and then the host.
I second what Richardson said. The upgrade path is vCenter (and all it's components) first, then the hosts.
I typically recommend rebuilding the hosts instead of doing upgrades. If your hosts have local VMs, then usually an in-place upgrade is easier.
Hardware is good to go. I was able to speak with VMWare support tech for a short time today. I had just finished verifing the hardware when the tech called me. He has talked me into going full boat upgrade 5.5.U2b. I have to up setup a new SQL Express 2008 first. I have the downloads for ESXi and vCenter Server for 5.5.U2b. Only thing I've been told is that this will break my current SRM. SRM will need to be built from the ground up. I think I'd have to do that anyway. My Equal Logic storage is doing the production vm replication of the volumes. I think the current SRM just builds off of the replicated vm's and presents me with test vm's. The SRM is only a best guess on my part at this time. But if I can keep production going and get it upgraded, it will buy me time to firgure out how to setup SRM later.
I'm on my way through the upgrade process now. For this reason I'll not need to maintain this request post any longer. I have ran into a few issues but nothing worth commenting on. I'd like to take this time to thank all of you who have included yourselves in my post. I do appriciate your asistance.