The traditional pension plan is a fantastic benefit if you intend to work 25-30 years, but a central tenet of this blog is that by saving 50% or more of your pay you can do it in 10-15 years. With $536,000 in investments already, you are WELL ahead on that front and could be there in just a few years. If your expenses are low enough, you may be very close.
Also, I highly suggest looking at the vesting period to determine if the pension plan really is all-or-nothing. Many plans allow you to take a reduced benefit without having to put in a full 25 or 30 years, as long as you're vested. I opted to leave early, deferring the pension until traditional retirement age. It will be lower, of course, than if I had worked 30 years, but it will still be a non-trivial amount to provide some guaranteed income for life.