To a certain degree we all have faced issues with ESX hosts however nothing can be more dramatic that not being able to connect to the hosts using VI Client, either directly or via VCenter. The old and good SSH or iLO now takes place.
I have unadvertisedly in the past deleted the Service Console and without pre-scripted instructions the re-creation job took a long time.
Luckily or unluckily ESXi does not suffer from this problem since there is no Service Console to be deleted. Apparently this is the way VMware promises to deliver new versions of it’s main virtualization product. Eric Siebert discusses this statement at http://itknowledgeexchange.techtarget.com/virtualization-pro/when-will-vmware-retire-the-esx-service-console/.
However if you lost your Service Console this post from Tom Howarth may just save your weekend as it did for me in the past. http://planetvm.net/blog/?p=423
If you are running VSphere 4.0 you will probably notice that SSH is not activated for the root user. This post from SEGET explains to ho activate it. http://www.vladan.fr/?p=2049
Have Fun and Break a Leg