It is important to take notice if suddenly boot times change, but trying to eke out every last second may result in you having to wait longer for other things to happen as they have nothing pre-loaded to speed that process up.
Actually the only tray items that aren't delayed are my A\V, power management icon, sound control and the stock Win 7 non-animated network indicator.
The delay items are DreamBreed Birthday reminder, process explorer, Virtual clone drive, Network-Activity- indicator, Notebook Hardware Control and CoreTemp.
NHC and CoreTemp are realtime monitoring apps.
Network-Activity-Indicator is an animated tray item like the old Vista and XP one.
The birthday reminder alerts me of upcoming birthdays 10 days in advance.
Virtual Clone Drive simply starts the VCD daemon.
Process Explorer is a Task Manager on steroids with a tray item.
I also run a shortcut to "C:\Windows\System32\w32tm.exe"/hide ""/resync"" ""/nowait""
to force Windows to update my system time at each boot since Windows doesn't seem to want to
consistently do it on it's own.
I use a tool called Winx32 to create a script that is then run 30 seconds after my desktop is fully functional.
Startup Delayer provides the delay.
None of these delayed apps are vital, they are just items I value in my system tray.
In total I have 10 items in my tray.