I was thinking about that tax hit, too. One move people often make is shifting some of that cash into municipal bonds. Because the income is usually tax-exempt, your "after-tax" return often beats that of a regular savings account.
It’s definitely a trade-off, though; you lose some of that instant liquidity, and the price can fluctuate. A good strategy is to split your funds: use cash for immediate needs and municipal bonds for long-term savings.