 compute the internal rate of return on the income stream. If you take the annuity versus the lump sum, I prefer the lump sum just because it gives you access to the money if you need it. And if you don't need it because you're living modestly and your pension plus your social security, when you take it covers all of your expenses, then you could just let it continue to grow and start giving it away or leave it as an inheritance or both.