Ask for another week vacation.

I probably wouldn't, but would instead negotiate on other things that were important to me like PTO.

I have a general rule to always ask for more during salary negotiations. As a hiring manager, I usually keep a little in my back pocket...and I assume others do as well. I just got an offer for comfortably above what I asked for. My instinct is not to ask for more, but I also know that in a few years I'll want to have maximized my salary.

Would you ask for more in this case?