Wise sages of 2+2 -- How much should one have saved before retiring?

[PokerPaul]

I know this varies greatly between individuals, but for interests sake and narrow it down assume the following:

- Someone making 85000 per annum pretax
- want to be able to live on 75% of that after retirement
- Must also take inflation into account
- In retirement, can still safely assume to bring in 18k annually from playing some poker for fun on the side.

What figure would one need to attain before one could contemplate retirement while achieving these goals?