The ISO of ESX 3.5 Update 3 is already available to download. I am sure that with this version, VMware made sure not to make the same mistakes again.

Among the new features are:

An increased limit from 8 to 20 vCPUs per core. While it may be of interest for some VDI environments with very low consumption, I think it’s very risky to have that many virtual machines per server.
VMDK Recovery Tool: Allows us to recover vmdks or VMFS volumes that were accidentally deleted;

Support for IBM SVC in both MRU and FIXED modes;

Support for new hardware, and

Support for Solaris 10U5, Ubuntu 8.04.1 and RHEL 4.7.

Release Notes:
http://www.vmware.com/support/vi3/doc/vi3_esx35u3_rel_notes.html

Thank you Alberto Gonzalez Martos for inspiring this article.