You haven't mentioned how much you currently have saved in tax-advantaged accounts, but *IF* you have significant tax-deferred savings already, AND if you plan to retire significantly earlier than 59.5, then I disagree with Dicey and terran. Here's why:
You're apparently already aware of the Roth Pipeline, and the need for 5x expenses. If your $150k is already more than 5x your annual expenses, then sure, go ahead and liquidate some of it (but keep 5x!), contribute to a tax-deferred account, and take the deduction. If it's less than 5x, then don't touch it, let it grow, and put all your savings (from wages) in tax-deferred accounts.
Depending on where your income lies in the various tax brackets, some other strategies might also be appropriate:
--If you're in the 12% bracket, and have space before you hit the 22% bracket, you could harvest some capital-gains to set a new, higher cost basis. This could prove important if current tax proposals pass into law and hike the LTCG tax rate.
--Similarly, if your savings rate isn't enough for you to max out your IRAs, and you have space in the 12% tax bracket, you could harvest capital gains and contribute to Roth IRAs, with the attendant tax benefit.