I just patched an ESXi 4.0 164009 Dell Customizations server with the three patches released 20090709 using the VMware vSphere Host Update Utility (gui tool).
Following the patching, it automatically rebooted and now the summary tab in vSphere Client has "Reboot Required", even though it auto rebooted and I followed up with a couple manual reboots.
I also notice a discrepancy in the build number. vSphere Client shows the build as '164009', however if I scan the server using the host update utility, it shows up as build 175625.
Update: I figured out how to 'solve' the problem. I had to exit out of vSphere Client and start it back up for the build number to change and for the "Reboot Required" message to go away. Strange that vSphere Client would require a restart of its own