I plan on doing the valve cover gaskets soon, so I'm starting a list of things to do while I'm in there. Here's what I can remember off the top of my head:
Pull fuel injectors to clean them and install new seals
Check knock sensor and all other visible wires. Some folks would probably replace the knock sensor wire and the temp sensor.
There's a hard coolant line that runs along the top end of motor. I'll take a good look at that for corrosion.
If I was really smart, I'd do the timing belt/water pump/ pulley kit since since the coolant is going to be drained anyway.
There is an oil leak around my distributor, so that will get a new o-ring.
The PO has already changed the PCV valve, but you might add that to your list
Vacuum lines, like you mentioned.
I'm sure there are a few more things to consider.