In Jan 2013, I made a poll to see how much of people's investable assets was in taxable accounts. The responses showed a fairly wide spread from less than 10% to nearly 100%.
See: Percentage of Taxable Money in Portfolio
I had 30% in savings that I could draw on until I could get my grubby fingers on my own IRA and 401k without penalty and without the rigidity of 72t distributions. I just checked again, and I am currently at 25%. The percentage change is due to expenses since then, but more importantly the taxable accounts include low-risk low-yield investments which have not kept up with the IRAs and 401k's accounts that are more heavily in equities.
I still have a couple of years till the age of 59-1/2 for IRA access, and more years till SS, but the money still left in taxable accounts should be enough for a while.