When you say rule of 55 - do you mean that your 401k plans specifically allow you to withdraw without penalty starting at 55? You need to check on that since the federal law *allows* rule of 55, it does not require it... so some plans don't allow it.
I disagree, to an extent, about only putting in match amount in your 401k... See the paragraph above - if your plan, does indeed, allow penalty withdrawals at age 55... ***AND*** you are in a highish tax bracket currently, and will be in a lower tax bracket after you retire at 55, you might want to put in more into your 401k than the match, to avoid higher current taxes. But you'll have to do some math to see the sweet spot. There is a benefit to having already-taxed money to work with - but not if you have to pay super high taxes on it. So maybe do 2/3's into your 401k, and 1/3 into a brokerage after-tax account... Do the math and estimate the taxes to figure out the sweet spot.
Is there a reason you aren't expecting any SS? There might be a haircut in the future - but it is unlikely they will eliminate it.